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While in addition we were trying to find a total, in subtraction we want to find a difference.
The difference between what, you may ask? Well consider the following three examples:
You just bought a ring for $215. You give the cashier $250. How much change will you get back?
We have to compute the difference between 250 and 215.
250 - 215 = 35.
You should get $35 back from the cashier.
A book contains 365 pages. You are currently on page 123. How much more do you have to read?
Now we have to compute the difference between 365 and 123.
365 - 123 = 242
You still have to read 242 pages.
On your floppy disk you have a total available memory of 959 KB. You have used 464 KB. How much memory do you have left on the floppy disk?
Now we are being asked to find the difference betweem 959 and 464.
959 - 464 = 495
You still have 495 KB of memory left on your disk.
See, anytime something changes values, you can compute a difference, and that means subtraction. In the above examples you saw a change in money, the number of pages in a book, and the amount of memory on a floppy disk.
Now it's time for you to compute some differences of your own.
To see a word problem, click on the "generate a subtraction word problem" button. Work out the problem and place your answer in the text box. Then click the "check my answer" button. The computer will then tell you whether or not your answer was correct. You will get additional instructions if your answer was incorrect.
After you complete the problem you can generate another word problem by clicking the "reset" button and then clicking the "generate a subtraction word problem" button once again.
Continue as many times as you wish, and then: