We included **HMH Into Math Grade 1 Answer Key PDF** **Module 12 Lesson 8 Use Mental Math to Find 10 Less and 10 More **to make students experts in learning maths.

## HMH Into Math Grade 1 Module 12 Lesson 8 Answer Key Use Mental Math to Find 10 Less and 10 More

I Can show 10 less or 10 more than a number without having to count.

**Step It Out**

Question 1.

March had 10 fewer rainy days than April. May had 10 more rainy days than April. April had 13 rainy days. How many rainy days were there in March and May?

A. April had 13 rainy days.

THINK: 13 is ___________ ten ________ ones.

Answer:

13 is 1 ten 3 ones

April has 13 rainy days

B. March had 10 less than April.

THINK: Take _________ ten away from 13.

Answer:

Take ten away

3 ones are left

March has 3 rainy days

C. May had 10 more than April.

THINK: Add __________ ten to 13.

Answer:

Add 10 more

There are 2 tens and 3 ones

May has 23 rainy days

D. Write the numbers.

Answer:

Explanation:

March had 10 fewer rainy days than April

May had 10 more rainy days than April

April had 13 rainy days

As shown above

March has 13 – 10

3 rainy days

May has 13 + 10

23 rainy days.

Question 2.

What numbers are 10 less and 10 more than 44?

A. Circle the number 44 on the hundred chart.

Answer:

B. What number is 10 less than 44? Circle the number.

THINK: Move up one row from 44.

Answer:

C. What number is 10 more than 44? Circle the number.

THINK: Move down one row from 44.

Answer:

D. Write the numbers to solve.

Answer:

Explanation:

10 more than 44 is 54

10 less than 44 is 34.

**Turn and Talk** Explain why the tens digit increases or decreases by 1 when 10 is added or subtracted from a number.

Answer:

The tens digit increases or decreases by 1 when 10 is added or subtracted from a number as 10 has 1 in tens digit and 0 in ones digit

As zero no value the number only changes with increase or decrease in tens digit.

**Check Understanding**

**Write the numbers that are 10 less and 10 more.**

Question 1.

_________ 25 ___________

Answer:

15 , 25, 35

Explanation:

10 less than 25 is 15

10 more than 25 is 35.

Question 2.

__________ 67 ___________

Answer:

57, 67, 77

Explanation:

10 less than 67 is 57

10 more than 67 is 77.

**On Your Own**

Question 3.

**Reason** Susan, Tracy, and Kris each have a rock collection. Susan has 48 rocks in her collection. Tracy has 10 more rocks than Susan. Kris has 10 more rocks than Tracy. How many rocks do Tracy and Kris each have?

A. Write the number of rocks Tracy and Kris have.

Tracy has ___________ rocks.

Kris has _________ rocks.

Answer:

Tracy has 58 rocks.

Kris has 68 rocks.

B. How many fewer rocks does Tracy have than Kris? Explain your reasoning.

Answer:

68 – 58 = 10

Explanation:

Susan, Tracy, and Kris each have a rock collection

Susan has 48 rocks in her collection

Tracy has 10 more rocks than Susan

48 + 10 = 58

Kris has 10 more rocks than Tracy

58 + 10 = 68

Tracy and Kris each have 58 and 68 rocks

68 – 58 = 10

So, Tracy have 10 fewer rocks than Kris.

**Write the numbers that are 10 less and 10 more.**

Question 4.

___________ 26 ___________

Answer:

16, 26, 36

Explanation:

10 less than 26 is 16

10 more than 26 is 36.

Question 5.

___________ 30 ___________

Answer:

20, 30, 40

Explanation:

10 less than 30 is 20

10 more than 30 is 40.

Question 6.

____________ 74 ___________

Answer:

64, 74, 84

Explanation:

10 less than 75 is 64

10 more than 74 is 84.

Question 7.

___________ 83 ___________

Answer:

73, 83, 93

Explanation:

10 less than 83 is 73

10 more than 83 is 93.

Question 8.

**Attend to Precision** Draw lines to match the card to the number.

Answer:

Explanation:

I drew lines to match the cards with their numbers.

**Write the numbers that are 10 less and 10 more.**

Question 9.

___________ 77 ___________

Answer:

67, 77, 87

Explanation:

10 less than 77 is 67

10 more than 77 is 87.

Question 10.

____________ 42 _____________

Answer:

32, 42, 52

Explanation:

10 less than 42 is 32

10 more than 42 is 52.

Question 11.

_____________ 59 ___________

Answer:

49, 59, 69

Explanation:

10 less than 59 is 49

10 more than 59 is 69.

Question 12.

_____________ 25 _____________

Answer:

15, 25, 35

Explanation:

10 less than 25 is 15

10 more than 25 is 35.