Episode 1 of 2
Subtraction on a calculator that leaves one digit's value
The question
Do subtraction on a calculator. Example: choose a 6-digit number and enter it on your calculator; each digit must be different, and the digit 0 must not be used. Say your number is 384 659.
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(a) Take away a number so that the answer is 9: 384 659 − 384 650 = 9.
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(b) Take away a number so that the answer is 80 000: 384 659 − 304 659 = 80 000. Next, choose a 6-digit number of your own and subtract in the same way. (a) My answer must be 500. (b) My answer must be 30 000.
Try it first, then show the answerHide the answer
Answer
- (a)247 593 − 247 093 = 500
- (b)438 216 − 408 216 = 30 000
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