Subtraction 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 ...
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.
Example
The temperature in Chicago one morning was \(73\) degrees Fahrenheit. A cold front arrived and by noon the temperature was \(27\) degrees Fahrenheit. What was the difference between the temperature in the morning and the temperature at noon?
Solution
We are asked to find the difference between the morning temperature and the noon temperature.
| Write a phrase. | the difference of 73 and 27 |
| Translate to math notation. Difference tells us to subtract. | \(73-27\) |
| Then we do the subtraction. | |
| Write a sentence to answer the question. | The difference in temperatures was 46 degrees Fahrenheit. |
Extra:
The high temperature on \(\mathrm{June}\phantom{\rule{0.2em}{0ex}}{1}^{\mathrm{st}}\) in Boston was \(77\) degrees Fahrenheit, and the low temperature was \(58\) degrees Fahrenheit. What was the difference between the high and low temperatures?
Solution
The difference is 19 degrees Fahrenheit.
Extra:
The weather forecast for June \(2\) in St Louis predicts a high temperature of \(90\) degrees Fahrenheit and a low of \(73\) degrees Fahrenheit. What is the difference between the predicted high and low temperatures?
Solution
The difference is 17 degrees Fahrenheit.
Example
A washing machine is on sale for \(\mathrm{$399}.\) Its regular price is \(\mathrm{$588}.\) What is the difference between the regular price and the sale price?
Solution
We are asked to find the difference between the regular price and the sale price.
| Write a phrase. | the difference between 588 and 399 |
| Translate to math notation. | \(588-399\) |
| Subtract. | |
| Write a sentence to answer the question. | The difference between the regular price and the sale price is $189. |
Extra:
A television set is on sale for \(\mathrm{$499}.\) Its regular price is \(\mathrm{$648}.\) What is the difference between the regular price and the sale price?
Solution
The difference is $149.
Extra:
A patio set is on sale for \(\mathrm{$149}.\) Its regular price is \(\mathrm{$285}.\) What is the difference between the regular price and the sale price?
Solution
The difference is $136.
This lesson is part of:
Introducing Numbers