# 3.2: How Many Pounds

Look at the pictures below.

Can you figure out the total number of pounds for the scale in the third picture (C)? In this concept, we will practice finding the total weight of collections of blocks.

### Guidance

In order to solve the problem above, use the problem solving steps.

- Start by
**describing**what information is given. - Then, identify what
**your job**is. In these problems, your job will be to figure out the total weight of the blocks in the third scale. - Next, make a
**plan**for how you will solve. In these problems, write the weight of each block on the block and then add the weights together to find the total weight. - Then,
**solve**the problem. - Finally,
**check**your solution.

#### Example A

Figure out the total number of pounds. Write the number on the scale.

**Solution:**

We can use the problem solving steps to help us with this problem.

#### Example B

Figure out the total number of pounds. Write the number on the scale.

**Solution:**

We can use the problem solving steps to help us with this problem.

#### Example C

Figure out the total number of pounds. Write the number on the scale.

**Solution:**

We can use the problem solving steps to help us with this problem.

#### Concept Problem Revisited

We can use the problem solving steps to help us with this problem.

### Vocabulary

** Substitution** is when you replace one object or value with an equal object or value. In this concept, we used substitution when we recorded the weight of each block on the actual block.

### Guided Practice

Figure out the total number of pounds on each scale. Write the number on the scale.

**Answers:**

- 20 pounds
- 18 pounds
- 22 pounds

### Practice

Use the following picture for problems 1-3.

Figure out the total number of pounds. Write the number on the scale.

Use the following picture for problems 4-6.

Figure out the total number of pounds. Write the number on the scale.

Use the following picture for problems 7-9.

Figure out the total number of pounds. Write the number on the scale.

Use the following picture for problems 10-12.

Figure out the total number of pounds. Write the number on the scale.

### Image Attributions

## Description

## Learning Objectives

Students determine the total weight of various collections of blocks by recording the weight of each block and adding these weights together. They will use the problem solving steps to solve. This is an early introduction to the concept of substitution, a key skill in algebra.