All the solutions provided in **McGraw Hill My Math Grade 3 Answer Key PDF Chapter 11 Lesson 4 Solve Mass Problems **will give you a clear idea of the concepts.

## McGraw-Hill My Math Grade 3 Answer Key Chapter 11 Lesson 4 Solve Mass Problems

**Math in My World**

**Example 1**

The bucket balance shows the mass of one marker. What is the mass of 5 markers?

Find the unknown. 8 × 5 = ____________.

A bucket balance can be used to determine mass.

Use mass weights on one side of the balance and the object on the other side. When the sides are balanced, the objects have the same mass.

Helpful Hint

You can also use repeated addition.

3 + 8 + 8 + 8 + 8 = 40

Five markers are 8 grams each. So multiply.

8 × 5 = ____________

The unknown is ____________ grams.

So, the mass of 5 markers is ____________ grams.

Answer:

Five markers are 8 grams each.

8 × 5 = 40 grams.

The unknown is 40 grams.

So, the mass of 5 markers is 40 grams.

**Example 2**

What is the total mass of the two pieces of fruit? Write an equation with a letter for the unknown. Then solve.

Add to find the unknown.

216 + 132 = f ← unknown

216 + 132 = _____________ grams

The unknown is _____________.

So, the two pieces of fruit have a combined mass of 348 grams.

Answer:

The mass of apple = 216 grams

The mass of the banana = 132 grams

216 + 132 = f

348 = f

216 + 132 = 348 grams

The unknown is 348 grams.

**Talk Math**

Explain how you solved Exercise 2.

Answer:

By using the addition operation we can find the total mass of the apple and banana.

216 + 132 = f

348 = f

216 + 132 = 348 grams

**Guided Practice**

**Algebra Write an equation with a letter for the unknown Then solve.**

Question 1.

What is the mass of 9 buttons?

Answer:

The mass of 1 box = 4 grams

The mass of 9 buttons = 4 × 9 = 36 grams

Thus the mass of 9 buttons = 36 grams

Question 2.

What is the mass of 1 jack?

Answer:

The mass of 6 jacks = 30 grams

The mass of 1 jack = 30/6 = 5 grams

**Independent Practice**

**Algebra Write an equation with a letter for the unknown. Then solve.**

Question 3.

What is the mass of two of these books?

Answer:

The mass of 1 book = 363 grams

The mass of 2 books = 363 × 2 = 726 grams

Question 4.

The golf ball has a mass of 45 grams. What is the mass of the baseball?

Answer:

The golf ball has a mass of 45 grams.

The mass of golf ball and baseball = 190 grams

190 – 45 = 145 grams

So, the mass of the baseball is 145 grams.

Question 5.

What is the mass of one of these dominoes?

Answer:

The mass of 6 dominoes = 66 grams

The mass of 1 dominoes = 66/6 = 11 grams

**Algebra Find each unknown.**

Question 6.

kilograms × 9 = 63 kilograms

The unknown is ______________.

Answer:

kilograms × 9 = 63 kilograms

= 63/9

= 7 kilograms

So, the unknown is 7 kilograms

Question 7.

392 grams + grams = 523 grams

The unknown is ______________.

Answer:

392 grams + grams = 523 grams

= 523 grams – 392 grams

= 131 grams

So, the unknown is 131 grams.

Question 8.

932 grams – grams = 149 grams

The unknown is ______________.

Answer:

932 grams – grams = 149 grams

= 932 grams – 149 grams

= 783 grams

So, the unknown is 783 grams

Question 9.

60 kilograms ÷ = 6 kilograms

The unknown is ______________.

Answer:

60 kilograms ÷ = 6 kilograms

= 60/6

= 10

So, the unknown is 10.

**Problem Solving**

Question 10.

A bucket balance shows that 2 rocks have a total mass of 732 grams. When 1 rock is removed, the bucket balance shows that the remaining rock is 428 grams. What is the mass of the rock that was removed?

Answer:

Given,

A bucket balance shows that 2 rocks have a total mass of 732 grams.

When 1 rock is removed, the bucket balance shows that the remaining rock is 428 grams.

732 – 428 = 304 grams

Thus the mass of the rock that was removed is 304 grams.

Question 11.

A student has a mass of 34 kilograms. An adult has a mass of 56 kilograms. What is the difference in mass between the student and adult?

Answer:

Given,

A student has a mass of 34 kilograms.

An adult has a mass of 56 kilograms.

56 – 34 = 22 kilograms

Thus the difference in mass between the student and adult is 22 kilograms

Question 12.

**Mathematical PRACTICE** Identify Structure A penny has a mass of about 3 grams. About how many grams would one dollar’s worth of pennies be? Write an equation with a letter for the unknown. Then solve.

Answer:

A penny has a mass of about 3 grams.

1 dollar = 100 pennies

100 × 3 = 300 pennies

**HOT Problems**

Question 13.

**Mathematical PRACTICE** Be Precise One button has a mass of 3 grams. What is the mass of one pencil?

Answer:

Given,

One button has a mass of 3 grams.

Mass of 7 buttons = 7 × 3 = 21 grams

3 + 2x = 21

2x = 21-3

2x = 19

x = 19/2

x = 9.5 grams

Thus the mass of one pencil = 9.5 grams

Question 14.

**Building on the Essential Question** When do you think it would be best to estimate the mass of an object and when would it be best to get an exact measure?

Answer:

When two objects are in the balancing measure then it is better to find the exact measure of the object.

If you have to measure the mass of the object using arithmetic operations then it is best to estimate the mass of the object.

### McGraw Hill My Math Grade 3 Chapter 11 Lesson 4 My Homework Answer Key

**Practice**

**Algebra Write an equation with a letter for the unknown. Then solve.**

Question 1.

What is the mass of 2 boxes of raisins?

Answer:

The mass of 1 box = 42 grams

The mass of 2 boxes = 42 × 2 = 84 grams

Question 2.

The scissors have a mass of 90 grams. What is the mass of the stapler?

Answer:

Given,

The scissors have a mass of 90 grams.

540 grams – 90 grams = 450 grams

Thus the mass of the stapler is 450 grams.

**Algebra Solve for the unknown.**

Question 3.

511 kilograms + = 720 kilograms

= _______________ kilograms

Answer:

511 kilograms + = 720 kilograms

= 720 kilograms – 511 kilograms

= 209 kilograms

Question 4.

90 grams ÷ = 10 grams

= ________________

Answer:

90 grams ÷ = 10 grams

= 90/10

= 9

Question 5.

grams – 138 grams = 704 grams

= ________________

Answer:

grams – 138 grams = 704 grams

= 704 + 138

= 842 grams

Question 6.

× 20 kilograms = 80 kilograms

= ________________

Answer:

× 20 kilograms = 80 kilograms

= 80/20

= 4

**Problem Solving**

Question 7.

Melinda’s pair of ski boots and skis have a mass of 6 kilograms. What is the mass of one ski boot and one ski?

Answer:

Given,

Melinda’s pair of ski boots and skis have a mass of 6 kilograms.

6/2 = 3

The mass of one ski boot and one ski is 3 kilograms.

Question 8.

A full bag of oatmeal has a mass of 560 grams. Cooper uses 80 grams of oatmeal to make breakfast for his family. What is the mass of the remaining oatmeal?

Answer:

Given,

A full bag of oatmeal has a mass of 560 grams.

Cooper uses 80 grams of oatmeal to make breakfast for his family.

560 – 80 = 480 grams

The mass of the remaining oatmeal is 480 grams.

Question 9.

Each bag can hold a mass of 3 kilograms. Wade has 24 kilograms of fruit to divide equally. How many bags will he need?

Answer:

Given,

Each bag can hold a mass of 3 kilograms.

Wade has 24 kilograms of fruit to divide equally.

24 ÷ 3 = 8

Thus he will need 8 bags.

Question 10.

**Mathematical PRACTICE** Use Number Sense Each of the four girls on Chantelle’s relay team got a swimming medal. One medal has a mass of 16 grams. What is the total mass of the relay team’s medals?

Answer:

Each of the four girls on Chantelle’s relay team got a swimming medal. One medal has a mass of 16 grams.

We have to use the multiplication operation here.

4 × 16 = 64 grams

So, the total mass of the relay team’s medals is 64 grams.

**Test Practice**

Question 11.

Jennifer’s cats eat 2 kilograms of food per month. How much food do the cats eat in 8 months?

(A) 4 kilograms

(B) 10 kilograms

(C) 14 kilograms

(D) 16 kilograms

Answer:

Given,

Jennifer’s cats eat 2 kilograms of food per month.

2 × 8 kg = 16 kg

Thus option D is the correct answer.