Go through the Math in Focus Grade 1 Workbook Answer Key Chapter 17 Addition and Subtraction to 100 to finish your assignments.

## Math in Focus Grade 1 Chapter 17 Answer Key Addition and Subtraction to 100

**Put On Your Thinking Cap!**

**Challenging Practice**

The Hundred Train is here! On its cars are two numbers that add to 100.

**Example**

There are many pairs of numbers that make 100. Write a pair of numbers on each train.

Question 1.

Answer:

45+55 = 100.

Explanation:

The pair of numbers that make 100 is 45 and 55.

Question 2.

Answer:

35+65 = 100.

Explanation:

The pair of numbers that make 100 is 35 and 65.

**Put On Your Thinking Cap!**

**Problem Solving**

Rosa buys stickers each day. She buys 1 sticker on the 1st day, 2 stickers on the 2nd day, 3 stickers on the 3rd day and 4 stickers on the 4th day. Rosa follows this pattern for 10 days. How many stickers does she have in all?

Answer:

The total number of stickers does she have in all is 55 stickers.

Explanation:

Given that Rosa buys stickers each day. She bought 1 sticker on the 1st day, 2 stickers on the 2nd day, 3 stickers on the 3rd day, and 4 stickers on the 4th day and the pattern follows for 10 days. So the number of stickers will be 1+2+3+4+5+6+7+8+9+10 which is 55 stickers.

**Chapter Review/Test**

**Concepts and Skills**

**Add.**

Question 1.

Answer:

56+3 = 59.

Explanation:

The sum of 56+3 is 59.

Question 2.

Answer:

30+50 = 80.

Explanation:

The sum of 30+50 is 80.

Question 3.

Answer:

47+30 = 77.

Explanation:

The sum of 47+30 is 77.

Question 4.

Answer:

61+14 = 75.

Explanation:

The sum of 61+14 is 75.

Question 5.

Answer:

74+9 = 83.

Explanation:

The sum of 74 and 9 is 83.

Question 6.

Answer:

53+27 = 80.

Explanation:

The sum of 53 and 27 is 80.

**Subtract.**

Question 7.

Answer:

67-5 = 62.

Explanation:

The subtraction of 67 and 5 is 62.

Question 8.

Answer:

80-20 = 60.

Explanation:

The subtraction of 80 and 20 is 60.

Question 9.

Answer:

93 – 20 = 73.

Explanation:

The subtraction of 93 and 20 is 73.

Question 10.

Answer:

87-11 = 76.

Explanation:

The subtraction of 87 and 11 is 76.

Question 11.

Answer:

75-9 = 66.

Explanation:

The subtraction of 75 and 9 is 66.

Question 12.

Answer:

90 – 68 = 22.

Explanation:

The subtraction of 90 and 68 is 22.