Questions tagged [mental-math]
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3
questions
3
votes
1answer
538 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 ...
4
votes
2answers
184 views
What's the word for addition and subtraction without borrowing or carrying over?
Is it regrouping? Upon googling it seems regrouping is borrowing or carrying over collectively. What's the word for not borrowing and carrying over? It's supposedly to train mental computation.
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19
votes
16answers
3k views
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 ...
