Go through the Math in Focus Grade 3 Workbook Answer Key Chapter 2 Practice 1 Mental Addition to finish your assignments.
Math in Focus Grade 3 Chapter 2 Practice 1 Answer Key Mental Subtraction
Add mentally. First, add the tens. Then, add the ones.
Example
Question 1.
24 + 55 = ?
24 + 50 = ___
___ + ___ = ___
So, 24 + 55 = ____
Answer:
24 + 50 = 74
74 + 5 = 79
So, 24 + 55 = 79
Question 2.
22 + 64 = ?
20 + 64 = ___
___ + ___ = ____
So, 22 + 64 = ___
Answer:
20 + 64 = 84
84 + 2 = 86
So, 22 + 64 = 86
Add mentally. Use number bonds to help you.
Example
Question 3.
37 + 45 = ?
37 + 50 = __
___ – ___ = ___
So, 37 + 45 = ___
Answer:
37 + 50 = 87
87 – 5 = 82
So, 37 + 45 = 82
Question 4.
46 + 34 = ?
46 + 40 = ___
__ – __ = ___
So 46 + 34 = ___
Answer:
46 + 40 = 86
86 – 6 = 80
So 46 + 34 = 80
Add mentally. Use number bonds to help you.
Question 5.
41 + 43 = ___
Answer:
41 + 43
40 + 40 = 80
80 + 1 + 3 = 84
So, 41 + 43 = 84
Question 6.
31 + 64 = ___
Answer:
31 + 64
30 + 60 = 90
90 + 1 + 5 = 95
So, 31 + 64 = 95
Question 7.
15 + 47 = ___
Answer:
15 + 47
15 + 50 = 65
65 – 3 = 62
So, 15 + 47 = 62
Question 8.
46 + 48 = ___
Answer:
46 + 48
50 + 50 = 100
100 – 4 -2 = 94
So, 46 + 48 = 94