Answers

2014-07-18T19:09:51+08:00
1) You must memorize multiplication table of many numbers for shortcuts
2) You better imagine that your solving somewhere.
3) Remember the numbers in your answer.

This is my answer it is just an opinion =)
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The Brainliest Answer!
2014-07-18T21:20:58+08:00
You can add numbers mentally by memorizing the multiplication table, addittion and subtraction table it worked GREAT for me
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