Thursday, February 17, 2011

Quick Subtraction Fact

Solve 321 - 123.
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You should end up with 198.

Here is another problem with a number where each digit decreases by one minus the same three numbers in reverse order. 876 - 678. Try it!
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You get 198 again!

Try to solve a 4-digit problem using the same pattern as above. What is your problem, and what do you get for your answer?

Then try it with 2, 5, 6, or even 7 digit numbers. After your solve the problems, comment below with what you find out.

                                                                      --Sydney

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