The cubes of numbers from 1 to 11 are easy to do in your head, right?
1, 8, 27, 64, 125, 216, 343, 512, 729, 1000, 1331
Some of the others are easy. Cubes of 20, 30, 40, 50, 60 - just add three zeros to cubes of 2, 3, 4, 5, 6.
16^3 is the same as 2^12, so 4096. (that's 4*1024 if you only know the powers of two up to 2^10)
32^3 is the same as 2^15, so 32,768. (assume you know the powers of two fairly high)
You just have to pick up the tricks.
2006-12-23 06:29:23
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answer #1
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answered by Steve A 7
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