This handy Spectrum Math Grade 4 Answer Key Chapter 1 Posttest provides detailed answers for the workbook questions.

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Adding and Subtracting 1 and 2 Digits

Question 1.
a.

Explanation:
Ones Place Value
3 + 7 = 10
Put the 0 in Ones place
Carry the 1 to Tens place
Tens Place Value
1 + 4 + 2 = 7
Put the 7 in Tens place

b.

Explanation:
Ones Place Value
7 + 1 = 8
Tens Place Value
5 + 2 = 7
Put the 7 in Tens place

c.

Explanation:
Ones Place Value
7 + 5 = 12
Put the 2 in Ones place
Carry the 1 to Tens place
Tens Place Value
1 + 3 + 1 = 5
Put the 5 in Tens place

d.

Explanation:
Ones Place Value
3 + 8 = 11
Put the 1 in Ones place
Carry the 1 to Tens place
Tens Place Value
1 + 7 + 2 = 10
Put the 0 in Tens place
Carry the 1 to Hundreds place

e.

Explanation:
Ones Place Value
6 + 3 = 9
Put the 9 in Ones place
Tens Place Value
5 + 4 = 9
Put the 9 in Tens place
Hundreds Place Value
2 = 2
Put the 2 in Hundreds place

f.

Explanation:
Ones Place Value
5 + 5 = 10
Put the 0 in Ones place
Carry the 1 to Tens place
Tens Place Value
1 + 7 + 2 = 10
Put the 0 in Tens place
Carry the 1 to Hundreds place
Hundreds Place Value
1 = 1
Put the 1 in Hundreds place

Question 2.

a.

Explanation:
Ones Place Value
3 + 0 + 8 = 11
Put the 1 in Ones place
Carry the 1 to Tens place
Tens Place Value
1 + 1 + 1 = 3
Put the 3 in Tens place

b.

Explanation:
Ones Place Value
7 + 5 + 3 = 15
Put the 5 in Ones place
Carry the 1 to Tens place
Tens Place Value
1 + 2 + 2 = 5
Put the 5 in Tens place

c.

Explanation:
Ones Place Value
8 + 8 = 16
Put the 6 in Ones place
Carry the 1 to Tens place
Tens Place Value
1 + 3 + 6 = 10
Put the 0 in Tens place
Carry the 1 to Hundreds place
Hundreds Place Value
1 + 2 = 3
Put the 3 in Hundreds place

d.

Explanation:
Ones Place Value
1 + 2 + 3 = 6
Put the 6 in Ones place
Tens Place Value
9 + 8 + 7 = 24
Put the 4 in Tens place
Carry the 2 to Hundreds place
Hundreds Place Value
2 = 2
Put the 2 in Hundreds place

e.

Explanation:
Ones Place Value
5 + 2 + 4 = 11
Put the 1 in Ones place
Carry the 1 to Tens place
Tens Place Value
1 + 0 + 9 + 1 = 11
Put the 1 in Tens place
Carry the 1 to Hundreds place
Hundreds Place Value
1 + 1 = 2
Put the 2 in Hundreds place

f.

Explanation:
Ones Place Value
6 + 8 = 14
Put the 4 in Ones place
Carry the 1 to Tens place
Tens Place Value
1 + 5 + 4 = 10
Put the 0 in Tens place
Carry the 1 to Hundreds place

Question 3.

a.

Explanation:
Ones Place Value
1 + 3 = 4
Put the 4 in Ones place
Tens Place Value
2 + 1 = 3
Put the 3 in Tens place

b.

Explanation:
Ones Place Value
3 + 2 = 5
Put the 5 in Ones place
Tens Place Value
5 + 4 = 9
Put the 9 in Tens place
Hundreds Place Value
2 = 2
Put the 2 in Hundreds place

c.

Explanation:
Ones Place Value
7 + 8 = 15
Put the 5 in Ones place
Carry the 1 to Tens place
Tens Place Value
1 + 3 + 2 = 6
Put the 6 in Tens place
Hundreds Place Value
1 = 1
Put the 1 in Hundreds place

d.

Explanation:
Ones Place Value
9 + 7 = 16
Put the 6 in Ones place
Carry the 1 to Tens place
Tens Place Value
1 + 7 + 9 = 17
Put the 7 in Tens place
Carry the 1 to Hundreds place

e.

Explanation:
Ones Place Value
3 + 8 = 11
Put the 1 in Ones place
Carry the 1 to Tens place
Tens Place Value
1 + 0 + 1 = 2
Put the 2 in Tens place
Hundreds Place Value
1 = 1
Put the 1 in Hundreds place

f.

Explanation:
Ones Place Value
5 + 7 = 12
Put the 2 in Ones place
Carry the 1 to Tens place
Tens Place Value
1 + 6 + 1 = 8
Put the 8 in Tens place

Question 4.
a.

Explanation:
Ones Place Value
3 + 1 + 0 = 4
Put the 4 in Ones place
Tens Place Value
7 + 2 + 1 = 10
Put the 0 in Tens place
Carry the 1 to Hundreds place
Hundreds Place Value
1 = 1
Put the 1 in Hundreds place

b.

Explanation:
Ones Place Value
2 + 8 = 10
Put the 0 in Ones place
Carry the 1 to Tens place
Tens Place Value
1 + 3 + 4 = 8
Put the 8 in Tens place
Hundreds Place Value
4 = 4
Put the 4 in Hundreds place

c.

Explanation:
Ones Place Value
4 + 8 + 2 = 14
Put the 4 in Ones place
Carry the 1 to Tens place
Tens Place Value
1 + 1 + 1 + 3 = 6
Put the 6 in Tens place

d.

Explanation:
Ones Place Value
6 + 4 = 10
Put the 0 in Ones place
Carry the 1 to Tens place
Tens Place Value
1 + 6 + 3 = 10
Put the 0 in Tens place
Carry the 1 to Hundreds place
Hundreds Place Value
1 = 1
Put the 1 in Hundreds place

e.

Explanation:
Ones Place Value
4 + 5 + 7 = 16
Put the 6 in Ones place
Carry the 1 to Tens place
Tens Place Value
1 + 3 + 4 + 5 = 13
Put the 3 in Tens place
Carry the 1 to Hundreds place
Hundreds Place Value
1 = 1
Put the 1 in Hundreds place

f.

Explanation:
Ones Place Value
3 + 4 = 7
Put the 7 in Ones place
Tens Place Value
1 + 7 = 8
Put the 8 in Tens place

Question 5.
a.

Explanation:
Subtract the ones we get 5 – 2 = 3
Subtract the tens we get 4 – 3 = 1
Subtract the hundreds we get 2 – 0 = 2
So, the difference of 245 and 32  is  213
245– 32= 213

b.

Explanation:
6 is greater than 5 so you must regroup:
Take 1 from 1, so 1 becomes 0.
Add 10 to 0, so 0 becomes 10.
Take 1 from 10, so 10 becomes 9.
Add 10 to 5, so 5 becomes 15.
15 minus 6 is 9
9 minus 1 is 8
0 minus 0 is 0

c.

Explanation:
Subtract the ones we get 5 – 2 = 3
Subtract the tens we get 3 – 1 = 2
So, the difference of 35 and 12is  23
35 – 12 = 23

d.

Explanation:
8 is greater than 2 so you must regroup:
Take 1 from 7, so 7 becomes 6.
Add 10 to 2, so 2 becomes 12.
12 minus 8 is 4
6 minus 2 is 4

e.

Explanation:
3 is greater than 1 so you must regroup:
Take 1 from 9, so 9 becomes 8.
Add 10 to 1, so 1 becomes 11.
11 minus 3 is 8
8 minus 7 is 1

f.

Explanation:
7 is greater than 5 so you must regroup:
Take 1 from 3, so 3 becomes 2.
Add 10 to 5, so 5 becomes 15.
15 minus 7 is 8
2 minus 0 is 2

Question 6.
a.

Explanation:
7 minus 4 is 3
3 is greater than 0 so you must regroup:
Take 1 from 1, so 1 becomes 0.
Add 10 to 0, so 0 becomes 10.
10 minus 3 is 7
0 minus 0 is 0

b.

Explanation:
5 is greater than 4 so you must regroup:
Take 1 from 9, so 9 becomes 8.
Add 10 to 4, so 4 becomes 14.
14 minus 5 is 9
8 minus 2 is 6

c.

Explanation:
6 is greater than 5 so you must regroup:
Take 1 from 1, so 1 becomes 0.
Add 10 to 5, so 5 becomes 15.
15 minus 6 is 9
2 is greater than 0 so you must regroup:
Take 1 from 2, so 2 becomes 1.
Add 10 to 0, so 0 becomes 10.
10 minus 2 is 8
1 minus 0 is 1

d.

Explanation:
9 is greater than 8 so you must regroup:
Take 1 from 8, so 8 becomes 7.
Add 10 to 8, so 8 becomes 18.
18 minus 9 is 9
7 minus 4 is 3

e.

Explanation:
8 is greater than 3 so you must regroup:
Take 1 from 7, so 7 becomes 6.
Add 10 to 3, so 3 becomes 13.
13 minus 8 is 5
6 minus 2 is 4
1 minus 0 is 1

f.

Explanation:
Subtract the ones we get 2 – 1 = 1
Subtract the tens we get 7 – 6 = 1
So, the difference of 72 and 61 is 11
72 – 61 = 11

Question 7.
a.

Explanation:
6 is greater than 5 so you must regroup:
Take 1 from 3, so 3 becomes 2.
Add 10 to 5, so 5 becomes 15.
15 minus 6 is 9
2 minus 1 is 1

b.

Explanation:
9 is greater than 8 so you must regroup:
Take 1 from 1, so 1 becomes 0.
Add 10 to 0, so 0 becomes 10.
Take 1 from 10, so 10 becomes 9.
Add 10 to 8, so 8 becomes 18
18 minus 9 is 9
9 minus 1 is 8
0 minus 0 is 0

c.

Explanation:
2 is greater than 1 so you must regroup:
Take 1 from 5, so 5 becomes 4.
Add 10 to 1, so 1 becomes 11.
11 minus 2 is 9
4 minus 3 is 1

d.

Explanation:
Subtract the ones we get 5 – 5 = 0
Subtract the tens we get 2 – 1 = 1
Subtract the hundreds we get 1 – 0 = 1
So, the difference of 125 and 15 is 110
125 – 15 = 110

e.

Explanation:
Subtract the ones we get 9 – 4 = 5
Subtract the tens we get 9 – 8 = 1
Subtract the hundreds we get 1 – 0 = 1
So, the difference of 199 and 84 is 115
199 – 84 = 115

f.

Explanation:
6 is greater than 4 so you must regroup:
Take 1 from 8, so 8 becomes 7.
Add 10 to 4, so 4 becomes 14.
14 minus 6 is 8
7 minus 2 is 5

Question 8.
a.

Explanation:
8 is greater than 7 so you must regroup:
Take 1 from 4, so 4 becomes 3.
Add 10 to 7, so 7 becomes 17.
17 minus 8 is 9
4 is greater than 3 so you must regroup:
Take 1 from 1, so 1 becomes 0.
Add 10 to 3, so 3 becomes 13.
13 minus 4 is 9
0 minus 0 is 0

b.

Explanation:
Subtract the ones we get 2 – 2 = 0
Subtract the tens we get 6 – 2 = 4
So, the difference of 62 and 22 is 40
62 – 22 = 40

c.

Explanation:
Subtract the ones we get 7 – 2 = 5
Subtract the tens we get 5 – 3 = 2
So, the difference of 57 and 32 is 25
57 – 32 = 25

d.

Explanation:
2 is greater than 1 so you must regroup:
Take 1 from 1, so 1 becomes 0.
Add 10 to 1, so 1 becomes 11.
11 minus 2 is 9
1 is greater than 0 so you must regroup:
Take 1 from 1, so 1 becomes 0.
Add 10 to 0, so 0 becomes 10
10 minus 1 is 9
0 minus 0 is 0

e.

Explanation:
8 is greater than 3 so you must regroup:
Take 1 from 2, so 2 becomes 1.
Add 10 to 3, so 3 becomes 13.
13 minus 8 is 5
4 is greater than 1 so you must regroup:
Take 1 from 1, so 1 becomes 0.
Add 10 to 1, so 1 becomes 11.
11 minus 4 is 7
0 minus 0 is 0

f.

Explanation:
9 is greater than 2 so you must regroup:
Take 1 from 9, so 9 becomes 8.
Add 10 to 2, so 2 becomes 12.
12 minus 9 is 3
8 minus 2 is 6

Solve each problem.

Question 9.
Tonya and her friends are collecting cans to recycle. Tonya has 55 cans, Irene has 32 cans, and Heather has 13 cans. How many cans do they have altogether?
They have __________ cans.
100
Explanation:
Tonya has 55 cans
Irene has 32 cans
and Heather has 13 cans
They have 100 cans.
55 + 32 + 13 = 100
They have altogether 100 cans.

Question 10.
The football team is raising money by running a car wash. They need to wash 210 cars to raise enough money. They have washed 98 cars already. How many more cars do they need to wash?
They need to wash __________ more cars.
112
Explanation:
The football team is raising money by running a car wash.
They need to wash 210 cars to raise enough money.
They have washed 98 cars already.
They need to wash 112 more cars.
210 – 98 = 112

Question 11.
Ms. Brooks’s science class is studying the environment around the school. Students counted 57 different plants and 25 different animals.
How many plants and animals did the class find altogether?
The class found ____ plants and animals.
82
Explanation:
Ms. Brooks’s science class is studying the environment around the school.
Students counted 57 different plants and 25 different animals.
Total number of plants and animals they found altogether are 82
The class found 82 plants and animals.
57 + 25 = 82

Question 12.
On a field trip, two sisters found frog eggs in a pond. Dee found 82 eggs and Shay found 118 eggs. How many frog eggs did they find?
They found ____ frog eggs.
200
Explanation:
On a field trip, two sisters found frog eggs in a pond.
Dee found 82 eggs and Shay found 118 eggs.
They found 200 frog eggs
82 + 118 = 200

Question 13.
At the bake sale, students brought in 115 cupcakes, 95 brownies, and 85 cookies. How many baked goods did the students bring in?
They brought in _________ baked goods.