Questions tagged [mental-math]

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20
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16answers
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Tricks for computing things in your head

There are quite a lot of tricks/shortcuts enabling doing calculations efficiently in your head. (One of them that came to me today is the "squaring a number ending with a 5" trick I wrote about in ...
4
votes
2answers
1k views

Determining the first digit of the Quotient using hand long division efficiently?

For instance in the following problem: _____ 48)4368 To determine an initial 9 for the first number in the Quotient, you ...