# Whole Numbers

## Subtract Whole Numbers


### Use Subtraction Notation

Suppose there are seven bananas in a bowl. Elana uses three of them to make a smoothie. How many bananas are left in the bowl? To answer the question, we subtract three from seven. When we subtract, we take one number away from another to find the difference. The notation we use to subtract  from  is
We read  as seven minus three and the result is the difference of seven and three.

### Model Subtraction of Whole Numbers

A model can help us visualize the process of subtraction much as it did with addition. Again, we will use  blocks. Remember a block represents 1 and a rod represents 10. Let’s start by modeling the subtraction expression we just considered, 

### Subtract Whole Numbers

Addition and subtraction are inverse operations. Addition undoes subtraction, and subtraction undoes addition.
We know  because  Knowing all the addition number facts will help with subtraction. Then we can check subtraction by adding. In the examples above, our subtractions can be checked by addition.
To subtract numbers with more than one digit, it is usually easier to write the numbers vertically in columns just as we did for addition. Align the digits by place value, and then subtract each column starting with the ones and then working to the left.
When we modeled subtracting  from  we exchanged  ten for  ones. When we do this without the model, we say we borrow  from the tens place and add  to the ones place.

### Translate Word Phrases to Math Notation

As with addition, word phrases can tell us to operate on two numbers using subtraction. To translate from a word phrase to math notation, we look for key words that indicate subtraction. Some of the words that indicate subtraction are listed in .

### Subtract Whole Numbers in Applications

To solve applications with subtraction, we will use the same plan that we used with addition. First, we need to determine what we are asked to find. Then we write a phrase that gives the information to find it. We translate the phrase into math notation and then simplify to get the answer. Finally, we write a sentence to answer the question, using the appropriate units.

### Key Concepts

1. Subtract whole numbers.


### Practice Makes Perfect

Use Subtraction Notation 
In the following exercises, translate from math notation to words.
Model Subtraction of Whole Numbers 
In the following exercises, model the subtraction.
Subtract Whole Numbers 
In the following exercises, subtract and then check by adding.
Translate Word Phrases to Algebraic Expressions 
In the following exercises, translate and simplify.
Mixed Practice 
In the following exercises, simplify.
In the following exercises, translate and simplify.
Subtract Whole Numbers in Applications 
In the following exercises, solve.

### Everyday Math


### Writing Exercises


### Self Check

ⓐ After completing the exercises, use this checklist to evaluate your mastery of the objectives of this section.

ⓑ What does this checklist tell you about your mastery of this section? What steps will you take to improve?
