All the solutions provided in **McGraw Hill Math Grade 2 Answer Key PDF Chapter 6 Lesson 3 Mentally Add 10 or 100** will give you a clear idea of the concepts.

## McGraw-Hill My Math Grade 2 Answer Key Chapter 6 Lesson 3 Mentally Add 10 or 100

**Explore and Explain**

**Teacher Directions:** Model using base-ten blocks. 126 students are waiting in line for the yellow buses and 126 students are also waiting for the green buses. 100 more students get in line for the yellow buses. 10 more students get in line for the green buses. How many students are in line for each bus now? Write the numbers.

Answer:

There are 226 students for yellow buses and 136 students for green buses.

Explanation:

Given that 126 students are waiting in line for the yellow buses and 126 students are also waiting for the green buses and 100 more students get in line for the yellow buses. which is 126+100 = 226 students and 10 more students get in line for the green buses which is 126+10 = 136 students. So there are 226 students for yellow buses and 136 students for green buses.

**See and Show**

To add 10 or 100, think of addition facts you know.

Mentally add 100.

Helpful Hint

you know that 2 + 1 = 3.

Mentally add 10.

**Helpful Hint**

You know that 5 + 1 = 6.

**Add.**

Question 1.

Answer:

450+100 = 550.

Explanation:

Here we need to add 100, so we will mentally add 100 to 450 which is 4+1 = 5. So 450+100 = 550.

Question 2.

Answer:

630 + 10 = 640.

Explanation:

Here we need to add 10, so we will mentally add 10 to 630 which is 3+1 = 4. So 630+10 = 640.

Question 3.

Answer:

801 + 100 = 901.

Explanation:

Here we need to add 100, so we will mentally add 100 to 801 which is 8+1 = 9. So 801+100 = 901.

Question 4.

Answer:

115 + 10 = 125.

Explanation:

Here we need to add 10, so we will mentally add 10 to 115 which is 1+1 = 2. So 115+10 = 125.

Question 5.

Answer:

500 + 10 = 510.

Explanation:

Here we need to add 10, so we will mentally add 10 to 500 which is 0+1 = 5. So 500+10 = 510.

Question 6.

Answer:

237 + 100 = 337.

Explanation:

Here we need to add 100, so we will mentally add 100 to 237 which is 2+1 = 3. So 237+100 = 337.

Question 7.

327 + 100 = ____

Answer:

327 + 100 = 427.

Explanation:

Here we need to add 100, so we will mentally add 100 to 327 which is 3+1 = 4. So 327+100 = 427.

Question 8.

755 + 10 = ____

Answer:

755 + 10 = 765.

Explanation:

Here we need to add 10, so we will mentally add 10 to 755 which is 5+1 = 6. So 755+10 = 765.

**Talk Math** Why is it easy to mentally add 10 or 100?

Answer:

It is easy to mentally add 10 or 100, because for adding mentally 10 we will add tens place digit only and for adding mentally 100 we will add hundreds place digit. So it is easy to mentally add 10 or 100.

**On My Math**

**Add.**

Question 9.

Answer:

122 + 100 = 222.

Explanation:

Here we need to add 100, so we will mentally add 100 to 122 which is 1+1 = 2. So 122+100 = 222.

Question 10.

Answer:

378 + 10 = 388.

Explanation:

Here we need to add 10, so we will mentally add 10 to 378 which is 7+1 = 8. So 378+10 = 388.

Question 11.

Answer:

500 + 10 = 510.

Explanation:

Here we need to add 10, so we will mentally add 10 to 500 which is 0+1 = 1. So 500+10 = 510.

Question 12.

Answer:

200 + 100 = 300.

Explanation:

Here we need to add 100, so we will mentally add 100 to 200 which is 2+1 = 3. So 200+100 = 300.

Question 13.

Answer:

747 + 100 = 847.

Explanation:

Here we need to add 100, so we will mentally add 100 to 747 which is 7+1 = 8. So 747+100 = 847.

Question 14.

Answer:

800 + 10 = 810.

Explanation:

Here we need to add 10, so we will mentally add 10 to 800 which is 0+1 = 1. So 800+10 = 810.

Question 15.

Answer:

400 + 10 = 410.

Explanation:

Here we need to add 10, so we will mentally add 10 to 400 which is 0+1 = 1. So 400+10 = 410.

Question 16.

Answer:

668 + 100 = 768.

Explanation:

Here we need to add 100, so we will mentally add 100 to 668 which is 6+1 = 7. So 668+100 = 768.

Question 17.

Answer:

817 + 100 = 917.

Explanation:

Here we need to add 100, so we will mentally add 100 to 817 which is 8+1 = 9. So 817+100 = 917.

**Find the missing addend.**

Question 18.

392 + ______ = 492

Answer:

392 + 100 = 492.

Explanation:

To find the missing addend we will subtract the addend from the sum. So 492-392 is 100. The missing addend is 100.

Question 19.

______ + 10 = 825

Answer:

815 + 10 = 825.

Explanation:

To find the missing addend we will subtract the addend from the sum. So 825-10 is 815. The missing addend is 815.

Question 20.

101 + ______ = 111

Answer:

101 + 10 = 111.

Explanation:

To find the missing addend we will subtract the addend from the sum. So 111-101 is 10. The missing addend is 10.

Question 21.

756 + ______ = 856

Answer:

756 + 100 = 856.

Explanation:

To find the missing addend we will subtract the addend from the sum. So 856-756 is 100. The missing addend is 100.

Question 22.

_____ + 100 = 823

Answer:

723 + 100 = 823.

Explanation:

To find the missing addend we will subtract the addend from the sum. So 823-100 is 723. The missing addend is 723.

Question 23.

_____ + 10 = 846

Answer:

836 + 10 = 846.

Explanation:

To find the missing addend we will subtract the addend from the sum. So 846-10 is 836. The missing addend is 836.

Question 24.

385 + _______ = 485

Answer:

385 + 100 = 485.

Explanation:

To find the missing addend we will subtract the addend from the sum. So 485-385 is 100. The missing addend is 100.

**Problem Solving**

Question 25.

448 birds are in the park. 100 more birds fly into the park. How many birds are in the park now?

___ birds

Answer:

448+100 = 548 birds.

Explanation:

Given that 448 birds are in the park and 100 more birds fly into the park. So the number of birds in the park now is 448+100 which is 548 birds.

Question 26.

A mail carrier delivered 352 packages last month. She delivered 10 more packages last week. How many packages did she deliver in all?

____ packages

Answer:

362 packages.

Explanation:

Given that a mail carrier delivered 352 packages last month as she delivered 10 more packages last week. The number of packages did she delivered in all is 352+10 which is 362 packages.

Question 27.

There are 112 sheep in a barn. More sheep come into the barn. Now there are 122 sheep. How many sheep came into the barn?

____ sheep

Answer:

The number of sheep that came into the barn is 10 sheep.

Explanation:

Given that there are 112 sheep in a barn as more sheep come into the barn. Now there are 122 sheep. So the number of sheep that came into the barn is 122-112 which is 10 sheep.

**Write Math** Explain how to add 100 to 899.

Answer:

899 – 100 = 799.

Explanation:

We will add 100 mentally to 899 which is 8-1 = 7. So 899-100 = 799.

### McGraw Hill My Math Grade 2 Chapter 6 Lesson 3 My Homework Answer Key

**Practice**

**Add.**

Question 1.

Answer:

235 + 100 = 335.

Explanation:

Here we need to add 100, so we will mentally add 100 to 235 which is 2+1 = 3. So 235+100 = 335.

Question 2.

Answer:

370 + 10 = 380.

Explanation:

Here we need to add 10, so we will mentally add 10 to 370 which is 7+1 = 8. So 370+10 = 380.

Question 3.

Answer:

532 + 100 = 632.

Explanation:

Here we need to add 100, so we will mentally add 100 to 532 which is 5+1 = 6. So 532+100 = 632.

Question 4.

Answer:

365 + 10 = 375.

Explanation:

Here we need to add 10, so we will mentally add 10 to 365 which is 6+1 = 7. So 365+10 = 375.

Question 5.

Answer:

178 + 100 = 278.

Explanation:

Here we need to add 100, so we will mentally add 100 to 178 which is 1+1 = 2. So 178+100 = 278.

Question 6.

Answer:

600 + 10 = 610.

Explanation:

Here we need to add 10, so we will mentally add 10 to 600 which is 0+1 = 5. So 600+10 = 610.

**Find the missing addend.**

Question 7.

389 + ___ = 489

Answer:

389 + 100 = 489.

Explanation:

To find the missing addend we will subtract the addend from the sum. So 489-389 is 100. The missing addend is 100.

Question 8.

____ + 10 = 235

Answer:

225 + 10 = 235.

Explanation:

To find the missing addend we will subtract the addend from the sum. So 235-10 is 225. The missing addend is 225.

Question 9.

634 + ____ = 644

Answer:

634 + 10 = 644.

Explanation:

To find the missing addend we will subtract the addend from the sum. So 644-634 is 10. The missing addend is 10.

Question 10.

295 + ____ = 395

Answer:

295 + 100 = 395.

Explanation:

To find the missing addend we will subtract the addend from the sum. So 395-295 is 100. The missing addend is 100.

Question 11.

Jackson has 389 ants in his ant farm. He puts 10 more ants in the farm. How many ants are in his ant farm now?

_____ ants

Answer:

The number of ants on his farm is 399 farms.

Explanation:

Given that Jackson has 389 ants on his ant farm and he puts 10 more ants on the farm. So the number of ants on his farm is 389+10 by adding mentally it will be 8+1 = 9. So 389+10 = 399 ants.

Question 12.

Ben has 115 pennies. His dad gives him more pennies. Now Ben has 215 pennies. How many pennies did his dad give him?

_____ pennies

Answer:

Ben dad’s gave him 100 pennies.

Explanation:

Given that Ben has 115 pennies and his dad gives him more pennies. Now Ben has 215 pennies. So the number of pennies will be 215-115 which is 100 pennies.

**Test Practice**

Question 13.

Find the sum.

825 + 100 = _____

(A) 725

(B) 900

(C) 925

(D) 920

Answer:

C.

Explanation:

Here we need to add 100, so we will mentally add 100 to 825 which is 8+1 = 9. So 825+100 = 925.

**Math at Home** Practice saying a number and having your child add 10 or 100 to the number mentally.

Answer:

218+10 = 228.

Explanation:

Let the number 218 and we will add 10 mentally. Here, we will add tens place digits of 2 numbers 1+1 = 2. So 218+10 = 228.