Students can use the **Spectrum Math Grade 3 Answer Key Chapter 2 Posttest** as a quick guide to resolve any of their doubts.

## Spectrum Math Grade 3 Chapter 2 Posttest Answers Key

**Check What You Learned**

**Adding and Subtracting 2- and 3-Digit Numbers (with renaming)**

**Add.**

Question 1.

a.

Answer:

Given numbers are 75 and 92

Let us add the digits in ones place first i.e. 5+2 = 7and then move on to the tens place. Adding these 2 addends we have the result as follows

b.

Answer:

Given numbers are 135 and 210

Let us add the digits in ones place first i.e. 5+0 = 5 and then move on to the tens place and hundreds place. Adding these 2 addends we have the result as follows

c.

Answer:

Given numbers are 193 and 56

Let us add the digits in ones place first i.e. 3+6 = 9 and then move on to the tens place and hundreds place. If you get carry shift it to the digit on top of tens place and in case of carry in tens place summation transfer it to hundreds place. Adding these 2 addends we have the result as follows

d.

Answer:

Given numbers are 310 and 92

Let us add the digits in ones place first i.e. 0+2 = 2 and then move on to the tens place and hundreds place. If you get carry shift it to the digit on top of tens place and in case of carry in tens place summation transfer it to hundreds place. Adding these 2 addends we have the result as follows

e.

Answer:

Given numbers are 513 and 409

Adding the units digits we have 3+9= 12. 2 is kept in the result of units digit and 1 is carry forwarded to top of tens place. Later, we will proceed further to tens place and hundreds place. Summing the numbers we get the result as under

f.

Answer:

Given numbers are 746 and 122

Adding the digits in units place first i.e. 6+2 = 8. As there is no carry we will proceed to tens place and then find the sum of them i.e. 4+2 = 6. Moving on to hundreds place we have the result as such

Question 2.

a.

Answer:

Given numbers are 193 and 86

Finding the sum of numbers we have the result as follows. Ones Place summation is 3+6 = 9 and hundreds place we have 9+8 = 17. Thus, we will move the carry ahead to hundreds place. Then adding the hundreds place we get 1+1 = 2. The final result is as below.

b.

Answer:

Given numbers are 183 and 192

Adding units digit we have 3+2 = 5

Summing the tens place we have = 8+9 = 17 where 1 is carry

Summing up the hundreds place and carry we get 1+1+1 = 3

Therefore, the result is as below

c.

Answer:

Given numbers are 842 and 908

Adding units digit we have 2+8 = 10 where 1 is carry

Summing the tens place we have = 4+0+1= 5

Summing up the hundreds place and carry we get 8+9 = 17

Therefore, the result is as below

d.

Answer:

Given numbers are 109 and 236

Adding units digit we have 9+6 = 15 where 1 is carry

Summing the tens place we have = 1+0+3= 4

Summing up the hundreds place and carry we get 1+2 = 3

Therefore, the result is as below

e.

Answer:

Given numbers are 963 and 310

Adding units digit we have 3+0 = 3

Summing the tens place we have = 6+1= 7

Summing up the hundreds place and carry we get 9+3 = 12

Therefore, the result is as below

f.

Answer:

Given numbers are 150 and 210

Adding units digit we have 0+0 = 0

Summing the tens place we have = 5+1= 6

Summing up the hundreds place and carry we get 1+2 = 3

Therefore, the result is as below

Question 3.

a.

Answer:

Given numbers are 512 and 457

Finding the sum of numbers in units digit we get 2+7 = 9

Adding Tens Place digits we have 1+5 = 6

Hundreds Place we have 5+4 = 9

the result is as follows

b.

Answer:

Given numbers are 310 and 97

Adding the given numbers starting from units digit and moving on to tens and hundreds place we have as below

c.

Answer:

Given numbers are 510 and 346

Summing beginning with units digit and then proceeding to tens and hundreds place we have the final result as below

d.

Answer:

Given numbers are 910 and 132

Adding the given numbers starting from units digit and moving on to tens and hundreds place we have as below

e.

Answer:

Given numbers are 512 and 403

Adding the given numbers starting from units digit and moving on to tens and hundreds place we have as below

f.

Answer:

Given numbers are 912 and 78

Finding the sum of these numbers beginning from ones place and proceeding further to tens and hundreds place we get as under

Question 4.

a.

Answer:

Adding numbers 543 and 286

Beginning with ones place and moving ahead to tens and hundreds place we get the result as follows

b.

Answer:

From given info we have the addends 123 and 592

Obtaining the sum of these numbers we have the result as follows

c.

Answer:

Given data is 647 and 382

Finding the sum of numbers 647 and 382 we get the result as under

d.

Answer:

Given data we have 442 and 85 as addends

Obtaining the summation of these addends we get the result as follows

e.

Answer:

Given addends are 123, 210 and 392

Finding the sum of units digits we have 3+0+2 = 5

Moving to tens place = 2+1+9 = 12 where 1 is carry

Moving on to hundreds place we get 1+1+2+3 = 7

f.

Answer:

Given addends are 212, 391 and 407

Finding the sum of units digits we have 2+1+7 = 10 where 1 is carry

Moving to tens place = 1+1+9+0 = 11 where 1 is carry

Moving on to hundreds place we get 1+2+3+4 = 10

Subtract.

Question 5.

a.

Answer:

Given numbers are 172 and 35

First let us subtract the units or ones digit. 2 is less than 5 so we can’t subtract thus we will take borrow from tens place making it 12. So, 12-5 = 7. Applying the same concept to tens place and hundreds place digit we have the result as follows

b.

Answer:

Given numbers are 192 and 86

First let us subtract the units or ones digit. 2 is less than 6 so we can’t subtract thus we will take borrow from tens place making it 12. So, 12-6 = 6. Applying the same concept to tens place and hundreds place digit we have the result as follows

c.

Answer:

Given numbers are 174 and 96

Let us find the difference of units place. As 4 is less than 6 we need to take borrow from tens place thus making it 14. Thus we have 14 – 6 = 8. Proceeding further to tens and hundreds place we get the result as follows

d.

Answer:

Given numbers are 120 and 80

Let us find the difference of units place. Thus we have 0-0 = 0. Proceeding further to tens and hundreds place we get the result as follows

e.

Answer:

Given numbers are 310 and 40

Subtracting the numbers in ones place we have 0-0 = 0.

Finding Difference of Tens Place digits we get as 11-4 = 7

f.

Answer:

Given numbers are 293 and 107

Difference between 293 and 107 in each steps is explained below

Question 6.

a.

Answer:

Given numbers are 986 and 698

Units digit subtraction we have 6 < 8. Taking borrow from tens place we get 16 – 8 = 8

In Tens Place we have after giving borrow 7. Since 7 < 9 Again taking borrow from hundreds place we have 17 i.e. 17 – 9 = 8

Hundreds Place Subtraction = 8-6 = 2

Thus, subtracting 698 from 986 we have the result as beneath

b.

Answer:

Given numbers are 862 and 245

Units digit subtraction we have 2 < 5. Taking borrow from tens place we get 12 – 5 = 7

In Tens Place we have after giving borrow 5. i.e. 5 – 4 = 1

Hundreds Place Subtraction = 8-2 = 6

Thus, subtracting 245 from 862 we have the result as beneath

c.

Answer:

Given numbers are 352 and 121

Units digit subtraction we have 2-1= 1

In Tens Place we have after giving borrow 5. i.e. 5 – 2= 3

Hundreds Place Subtraction = 3-1 = 2

Thus, subtracting 121 from 352 we have the result as beneath

d.

Answer:

Given numbers are 187 and 72

Units digit subtraction we have 7-2= 5

In Tens Place we have 8 – 7= 1

Thus, subtracting 72 from 187 we have the result as beneath

e.

Answer:

Given numbers are 647 and 253

Units digit subtraction we have 7-3= 4

In Tens Place we have 4 < 5 so we will take borrow making it 14 i.e. 14-5 = 9

Thus, subtracting 253 from 647 we have the result as beneath

f.

Answer:

Given numbers are 547 and 183

Units digit subtraction we have 7-3= 4

In Tens Place we have 4 < 8 so we will take borrow making it 14 i.e. 14-8 = 6

Hundreds Place after giving borrow is 4 i.e. 4-1 = 3

Thus, subtracting 183 from 547 we have the result as beneath

Question 7.

a.

Answer:

Given numbers are 662 and 503

Units digit subtraction we have 2 < 3. Thus, we will take borrow from tens place 12-3= 9

In Tens Place we have after giving borrow 5 i.e. 5-0 = 5

Hundreds Place 6- 5= 1

Thus, subtracting 503 from 662 we have the result as beneath

b.

Answer:

Given numbers are 708 and 231

Units digit subtraction we have 8-1= 7

In Tens Place we have 10 after taking borrow 10 – 3 = 7

Hundreds Place after giving borrow is 6 i.e. 6- 2 = 4

Thus, subtracting 231 from 708 we have the result as beneath

c.

Answer:

Given numbers are 456 and 269

Beginning with ones place and proceeding further to tens and hundreds place we have the subtraction as such

d.

Answer:

Here numbers to subtract are 882 and 199

Starting from ones place and then moving forward to tens and hundreds place we have the result as follows

e.

Answer:

Here we have the numbers 753 and 268

The steps involved in the subtraction of numbers is as follows

f.

Answer:

Given numbers are 712 and 543

We have to subtract from the right most place i.e. ones place and then move to tens and hundreds place digits. The process to do so is as explained

Question 8.

a.

Answer:

Given numbers are 712 and 402

Subtracting these 2 numbers we have the steps as below

b.

Answer:

Here the numbers to subtract from one another are 548 and 213

Beginning with ones place and moving to tens and hundreds place we have the result as below

c.

Answer:

Here the numbers are 593 and 369

The process to subtract these numbers is clearly mentioned below

d.

Answer:

Given digits are 610 and 132

The process to subtract each number from the other is mentioned beneath

e.

Answer:

Given numbers are 782 and 441

Subtracting the numbers is as follows and the steps involved are as such

f.

Answer:

Given numbers are 192 and 85

Subtracting them from each other is given in detailed steps below

**Solve each problem.**

Question 9.

For a game of checkers, 24 checkers are needed. There are only 18 checkers in the box. How many checkers are missing?

There are ___________ checkers missing.

Answer:

Number of checkers needed for game = 24

Number of checkers in box = 18

Number of checkers missing = number of checkers needed for game – number of checkers in box

= 24-18

= 6

Therefore, 6 checkers are needed.

Question 10.

An adult has 32 teeth. A child has 24 teeth. How many more teeth does an adult have?

An adult has __________ more teeth than a child.

Answer:

No. of teeth adult have = 32

No. of Child teeth have = 24

Number of teeth adult have more than a child = 32- 24

= 8

Therefore, number of teeth adult have more than a child is 8.

Question 11.

Sam weighed 232 pounds. He lost 13 pounds. How much does Sam weigh now?

Sam weighs ____ pounds.

Answer:

Sam Weighs = 232 Pounds

Number of Pounds Last = 13

Sam Weigh now = 232 – 13

= 219

Total Pounds Sam weighs now is 219

Question 12.

Alvin has 532 pennies. Regina has 691 pennies. How many pennies do they have together?

Alvin and Regina have ___ pennies together.

Answer:

Number of Pennies Alvin has = 532

Number of Pennies Regina has = 691

Total Pennies Alvin and Regina have together = 532+691

= 1223

Total Pennies Alvin and Regina have together in total is 1223

Question 13.

Mr. Ito is 53 years old. His daughter, Kimi, is 25. How much older is Mr. Ito than his daughter? Mr. Ito is ____ years older than his daughter.

Answer:

Age of Mr. Ito = 53

Age of his daughter Kimi = 25

Number of Years Mr. Ito is older than this daughter = Age of Mr. Ito – Age of His Daughter

= 53- 25

= 28

Mr. Ito is 28 years older than this daughter.

Question 14.

Mr. and Mrs. Acosta have been married for ‘47 years. Mrs. Acosta was 29 when she married Mr. Acosta. How old is Mrs. Acosta now?

Mrs. Acosta is ____ years old.

Answer:

Number of years Mr. and Mrs. Acosta are married = 47 years

Age of Mrs. Acosta when she is married = 29

Number of years Mrs. Acosta has = Age when she is married + No. of years of their Marriage

= 29+47

= 76

Therefore, Age of Mrs. Acosta is 76