Students can use the Spectrum Math Grade 3 Answer Key Chapter 1 Lesson 1.8 Addition and Subtraction Practice as a quick guide to resolve any of their doubts

Question 1.
a.

Explanation:
While doing subtraction, first we should subtract digits in one’s place and should move to the left i.e., to the ten’s place and so on. Now, subtract 0 from 3 where difference is equal to 3. So, 3 should be written in one’s digit in the answer. Now, moving to the left that is ten’s place, we have to subtract 1 from 2 which is 1. After subtracting the given two numbers the difference is equal to 13.

b.

Explanation:
First, we need to add the digits in one’s place. So, we need to add 6 and 1 which are in one’s place. Adding 6 and 1 gives the sum as 7. So, 7 will be placed in the one’s digit in the answer. Next, we need to add the digits in ten’s place. Adding 7 and 2 gives the sum 9. So, 9 should be written in ten’s place in the answer. So, the sum of given two numbers is 97.

c.

Explanation:
While doing subtraction, first we should subtract digits in one’s place and should move to the left i.e., to the ten’s place and so on. In one’s place, if we cannot subtract the subtrahend from minuend, then we should rename minuend as tens and ones. As we have 2 at one’s place in minuend, we can rename 82 as 7 tens and 12 ones. Now, subtract 9 from 12 where difference is equal to 3. So, 3 should be written in one’s digit in the answer. Now, moving to the left that is ten’s place, we have 7 tens. So, subtract 1 from 7 which is 6. So, the total difference is equal to 63.

d.

Explanation:
First, we need to add the digits in one’s place. So, we need to add 6, 7 and 3 which are in one’s place. Adding 6, 7 and 3 gives the sum as 16 which can be renamed as 10 + 6. So, 6 will be placed in the one’s digit in the answer 1 will be carry forwarded to get added with the numbers in ten’s place. So, adding digits in tens place which are 1 and 1 along with the carry forwarded digit 1 will give sum as 3. So, 3 should be written in ten’s place in the answer. Finally, the sum of given three numbers is 36.

e.

Explanation:
First, we need to add the digits in one’s place. So, we need to add 6 and 5 which are in one’s place. Adding 6 and 5 gives the sum as 11 which can be renamed as 10 + 1. So, 1 will be placed in the one’s digit in the answer and another 1 will be carry forwarded to get added with the numbers in ten’s place. So, adding digits in tens place which are 1 and 3 along with the carry forwarded digit 1 will give sum as 5. So, 5 should be written in ten’s place in the answer. Finally, the sum of given two numbers is 51.

f.

Explanation:
While doing subtraction, first we should subtract digits in one’s place and should move to the left i.e., to the ten’s place and so on. Now, subtract 0 from 6 where difference is equal to 6. So, 6 should be written in one’s digit in the answer. Now, moving to the left that is ten’s place, we have to subtract 3 from 7 which is 4. After subtracting the given two numbers the difference is equal to 46.

Question 2.
a.

Explanation:
First, we need to add the digits in one’s place. So, we need to add 0 and 0 which are in one’s place. Adding 0 and 0 gives the sum as 0. So, 0 will be placed in the one’s digit in the answer. Next, we need to add the digits in ten’s place. Adding 2 and 5 gives the sum 7. So, 7 should be written in ten’s place in the answer. So, the sum of given two numbers is 70.

b.

Explanation:
While doing subtraction, first we should subtract digits in one’s place and should move to the left i.e., to the ten’s place and so on. In one’s place, if we cannot subtract the subtrahend from minuend, then we should rename minuend as tens and ones. As we have 0 at one’s place in minuend, we can rename 30 as 2 tens and 10 ones. Now, subtract 3 from 10 where difference is equal to 7. So, 7 should be written in one’s digit in the answer. Now, moving to the left that is ten’s place, we have 2 tens. So, subtract 1 from 2 which is 1. So, the total difference is equal to 17.

c.

Explanation:
First, we need to add the digits in one’s place. So, we need to add 6, 3 and 3 which are in one’s place. Adding 6, 3 and 3 gives the sum as 12 which can be renamed as 10 + 2. So, 2 will be placed in the one’s digit in the answer 1 will be carry forwarded to get added with the numbers in ten’s place. So, adding digits in tens place which are 1, 1 and 2 along with the carry forwarded digit 1 will give sum as 5. So, 5 should be written in ten’s place in the answer. Finally, the sum of given three numbers is 52.

d.

Explanation:
While doing subtraction, first we should subtract digits in one’s place and should move to the left i.e., to the ten’s place and so on. Now, subtract 3 from 6 where difference is equal to 3. So, 3 should be written in one’s digit in the answer. Now, moving to the left that is ten’s place, we have to subtract 4 from 7 which is 3. After subtracting the given two numbers the difference is equal to 33.

e.

Explanation:
While doing subtraction, first we should subtract digits in one’s place and should move to the left i.e., to the ten’s place and so on. Now, subtract 5 from 7 where difference is equal to 2. So, 2 should be written in one’s digit in the answer. Now, moving to the left that is ten’s place, we have to subtract 4 from 8 which is 4. After subtracting the given two numbers the difference is equal to 42.

f.

Explanation:
While doing subtraction, first we should subtract digits in one’s place and should move to the left i.e., to the ten’s place and so on. In one’s place, if we cannot subtract the subtrahend from minuend, then we should rename minuend as tens and ones. As we have 2 at one’s place in minuend, we can rename 92 as 8 tens and 12 ones. Now, subtract 9 from 12 where difference is equal to 3. So, 3 should be written in one’s digit in the answer. Now, moving to the left that is ten’s place, we have 8 tens. So, subtract 7 from 8 which is 1. So, the total difference is equal to 13.

Question 3.
a.

Explanation:
First, we need to add the digits in one’s place. So, we need to add 6 and 8 which are in one’s place. Adding 6 and 8 gives the sum as 14 which can be renamed as 10 + 4. So, 4 will be placed in the one’s digit in the answer and 1 will be carry forwarded to get added with the numbers in ten’s place. So, adding digits in tens place which are 2 and 5 along with the carry forwarded digit 1 will give sum as 8. So, 8 should be written in ten’s place in the answer. Finally, the sum of given two numbers is 84.

b.

Explanation:
While doing subtraction, first we should subtract digits in one’s place and should move to the left i.e., to the ten’s place and so on. In one’s place, if we cannot subtract the subtrahend from minuend, then we should rename minuend as tens and ones. As we have 6 at one’s place in minuend, we can rename 96 as 8 tens and 16 ones. Now, subtract 7 from 16 where difference is equal to 9. So, 9 should be written in one’s digit in the answer. Now, moving to the left that is ten’s place, we have 8 tens. So, subtract 1 from 8 which is 7. So, the total difference is equal to 79.

c.

Explanation:
First, we need to add the digits in one’s place. So, we need to add 2 and 3 which are in one’s place. Adding 2 and 3 gives the sum as 5. So, 5 will be placed in the one’s digit in the answer. Next, we need to add the digits in ten’s place. Adding 7 and 0 gives the sum 7. So, 7 should be written in ten’s place in the answer. So, the sum of given two numbers is 75.

d.

Explanation:
First, we need to add the digits in one’s place. So, we need to add 9 and 8 which are in one’s place. Adding 9 and 8 gives the sum as 17 which can be renamed as 10 + 7. So, 7 will be placed in the one’s digit in the answer and 1 will be carry forwarded to get added with the numbers in ten’s place. So, adding digits in tens place which are 7 and 0 along with the carry forwarded digit 1 will give sum as 8. So, 8 should be written in ten’s place in the answer. Finally, the sum of given two numbers is 87.

e.

Explanation:
While doing subtraction, first we should subtract digits in one’s place and should move to the left i.e., to the ten’s place and so on. In one’s place, if we cannot subtract the subtrahend from minuend, then we should rename minuend as tens and ones. As we have 6 at one’s place in minuend, we can rename 16 as 0 tens and 16 ones. Now, subtract 8 from 16 where difference is equal to 8. So, 8 should be written in one’s digit in the answer. Now, moving to the left that is ten’s place, we have 0 tens. So, subtract 0 from 0 which is 0. So, the total difference is equal to 8.

f.

Explanation:
First, we need to add the digits in one’s place. So, we need to add 8, 2 and 2 which are in one’s place. Adding 8, 2 and 2 gives the sum as 12 which can be renamed as 10 + 2. So, 2 will be placed in the one’s digit in the answer 1 will be carry forwarded to get added with the numbers in ten’s place. So, adding digits in tens place which are 1, 1 and 4 along with the carry forwarded digit 1 will give sum as 7. So, 7 should be written in ten’s place in the answer. Finally, the sum of given three numbers is 72.

Question 4.
a.

Explanation:
While doing subtraction, first we should subtract digits in one’s place and should move to the left i.e., to the ten’s place and so on. In one’s place, if we cannot subtract the subtrahend from minuend, then we should rename minuend as tens and ones. As we have 6 at one’s place in minuend, we can rename 86 as 7 tens and 16 ones. Now, subtract 9 from 16 where difference is equal to 7. So, 7 should be written in one’s digit in the answer. Now, moving to the left that is ten’s place, we have 7 tens. So, subtract 1 from 7 which is 6. So, the total difference is equal to 67.

b.

Explanation:
First, we need to add the digits in one’s place. So, we need to add 7 and 6 which are in one’s place. Adding 7 and 6 gives the sum as 13 which can be renamed as 10 + 3. So, 3 will be placed in the one’s digit in the answer and 1 will be carry forwarded to get added with the numbers in ten’s place. So, adding digits in tens place which are 7 and 1 along with the carry forwarded digit 1 will give sum as 9. So, 9 should be written in ten’s place in the answer. Finally, the sum of given two numbers is 93.

c.

Explanation:
While doing subtraction, first we should subtract digits in one’s place and should move to the left i.e., to the ten’s place and so on. In one’s place, if we cannot subtract the subtrahend from minuend, then we should rename minuend as tens and ones. As we have 3 at one’s place in minuend, we can rename 43 as 3 tens and 13 ones. Now, subtract 9 from 13 where difference is equal to 4. So, 4 should be written in one’s digit in the answer. Now, moving to the left that is ten’s place, we have 3 tens. So, subtract 2 from 3 which is 1. So, the total difference is equal to 14.

d.

Explanation:
First, we need to add the digits in one’s place. So, we need to add 6 and 7 which are in one’s place. Adding 6 and 7 gives the sum as 13 which can be renamed as 10 + 3. So, 3 will be placed in the one’s digit in the answer and 1 will be carry forwarded to get added with the numbers in ten’s place. So, adding digits in tens place which are 1 and 0 along with the carry forwarded digit 1 will give sum as 2. So, 2 should be written in ten’s place in the answer. Finally, the sum of given two numbers is 23.

e.

Explanation:
While doing subtraction, first we should subtract digits in one’s place and should move to the left i.e., to the ten’s place and so on. Now, subtract 2 from 2 where difference is equal to 0. So, 0 should be written in one’s digit in the answer. Now, moving to the left that is ten’s place, we have to subtract 4 from 8 which is 4. After subtracting the given two numbers the difference is equal to 40.

f.

Explanation:
While doing subtraction, first we should subtract digits in one’s place and should move to the left i.e., to the ten’s place and so on. In one’s place, if we cannot subtract the subtrahend from minuend, then we should rename minuend as tens and ones. As we have 6 at one’s place in minuend, we can rename 86 as 7 tens and 16 ones. Now, subtract 9 from 16 where difference is equal to 7. So, 7 should be written in one’s digit in the answer. Now, moving to the left that is ten’s place, we have 7 tens. So, subtract 3 from 7 which is 4. So, the total difference is equal to 47.

Question 5.
a.

Explanation:
While doing subtraction, first we should subtract digits in one’s place and should move to the left i.e., to the ten’s place and so on. Now, subtract 3 from 7 where difference is equal to 4. So, 4 should be written in one’s digit in the answer. Now, moving to the left that is ten’s place, we have to subtract 4 from 5 which is 1. After subtracting the given two numbers the difference is equal to 14.

b.

Explanation:
First, we need to add the digits in one’s place. So, we need to add 9 and 9 which are in one’s place. Adding 9 and 9 gives the sum as 18. So, the sum of given two numbers is 18.

c.

Explanation:
First, we need to add the digits in one’s place. So, we need to add 0 and 0 which are in one’s place. Adding 0 and 0 gives the sum as 0. So, 0 will be placed in the one’s digit in the answer. Next, we need to add the digits in ten’s place. Adding 0 and 3 gives the sum 3. So, 3 should be written in ten’s place in the answer. So, the sum of given two numbers is 30.

d.

Explanation:
While doing subtraction, first we should subtract digits in one’s place and should move to the left i.e., to the ten’s place and so on. In one’s place, if we cannot subtract the subtrahend from minuend, then we should rename minuend as tens and ones. As we have 1 at one’s place in minuend, we can rename 41 as 3 tens and 11 ones. Now, subtract 2 from 11 where difference is equal to 9. So, 9 should be written in one’s digit in the answer. Now, moving to the left that is ten’s place, we have 3 tens. So, subtract 2 from 3 which is 1. So, the total difference is equal to 19.

e

Explanation:
First, we need to add the digits in one’s place. So, we need to add 8, 2 and 3 which are in one’s place. Adding 8, 2 and 3 gives the sum as 13 which can be renamed as 10 + 3. So, 3 will be placed in the one’s digit in the answer 1 will be carry forwarded to get added with the numbers in ten’s place. So, adding digits in tens place which are 1, 4 and 1 along with the carry forwarded digit 1 will give sum as 7. So, 7 should be written in ten’s place in the answer. Finally, the sum of given three numbers is 73.

f.

Explanation:
First, we need to add the digits in one’s place. So, we need to add 8 and 3 which are in one’s place. Adding 8 and 3 gives the sum as 11 which can be renamed as 10 + 1. So, 1 will be placed in the one’s digit in the answer and 1 will be carry forwarded to get added with the numbers in ten’s place. So, adding digits in tens place which are 1 and 5 along with the carry forwarded digit 1 will give sum as 7. So, 7 should be written in ten’s place in the answer. Finally, the sum of given two numbers is 71.

Question 6.
a.

Explanation:
While doing subtraction, first we should subtract digits in one’s place and should move to the left i.e., to the ten’s place and so on. In one’s place, if we cannot subtract the subtrahend from minuend, then we should rename minuend as tens and ones. As we have 1 at one’s place in minuend, we can rename 81 as 7 tens and 11 ones. Now, subtract 9 from 11 where difference is equal to 2. So, 2 should be written in one’s digit in the answer. Now, moving to the left that is ten’s place, we have 7 tens. So, subtract 7 from 7 which is 0. So, the total difference is equal to 2.

b.

Explanation:
First, we need to add the digits in one’s place. So, we need to add 7 and 4 which are in one’s place. Adding 7 and 4 gives the sum as 11 which can be renamed as 10 + 1. So, 1 will be placed in the one’s digit in the answer and 1 will be carry forwarded to get added with the numbers in ten’s place. So, adding digits in tens place which are 2 and 3 along with the carry forwarded digit 1 will give sum as 6. So, 6 should be written in ten’s place in the answer. Finally, the sum of given two numbers is 61.

c.

Explanation:
First, we need to add the digits in one’s place. So, we need to add 6 and 3 which are in one’s place. Adding 6 and 3 gives the sum as 9. So, 9 will be placed in the one’s digit in the answer. Next, we need to add the digits in ten’s place. Adding 8 and 1 gives the sum 9. So, 9 should be written in ten’s place in the answer. So, the sum of given two numbers is 99.

d.

Explanation:
While doing subtraction, first we should subtract digits in one’s place and should move to the left i.e., to the ten’s place and so on. In one’s place, if we cannot subtract the subtrahend from minuend, then we should rename minuend as tens and ones. As we have 2 at one’s place in minuend, we can rename 92 as 8 tens and 12 ones. Now, subtract 6 from 12 where difference is equal to 6. So, 6 should be written in one’s digit in the answer. Now, moving to the left that is ten’s place, we have 8 tens. So, subtract 3 from 8 which is 5. So, the total difference is equal to 56.

e.