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Step 6Multiply
"But wait," I hear you cry, "this Instructable is meant to be about adding!"
But we've already invented a handful of new digits and borrowed numbers from out of thin air, so a simple multiplication shouldn't be too hard.
What is 55+66? The conventional method involves lots of carries and is (like many of the examples in this Instructable) a bit awkward. However, I'm sure many people will notice that 55 is 11*5 and 66 is 11*6, so the sum is naturally 11*11. Depending on how far your multiplication tables went you may know 11*11=121 off the top of your head, but other multiplications (the 5 and 9 times table, for instance) feature a lot of rules for working them out so may be of use in this technique.
63+18 might be a pain to work out in your head explicitly but a knowledge of the 9 times table will tell you that it is 7*9 + 1*9 = 9*9 = 81. For small numbers this method may not be much quicker than simple addition but certain problems may be greatly simplified.
But we've already invented a handful of new digits and borrowed numbers from out of thin air, so a simple multiplication shouldn't be too hard.
What is 55+66? The conventional method involves lots of carries and is (like many of the examples in this Instructable) a bit awkward. However, I'm sure many people will notice that 55 is 11*5 and 66 is 11*6, so the sum is naturally 11*11. Depending on how far your multiplication tables went you may know 11*11=121 off the top of your head, but other multiplications (the 5 and 9 times table, for instance) feature a lot of rules for working them out so may be of use in this technique.
63+18 might be a pain to work out in your head explicitly but a knowledge of the 9 times table will tell you that it is 7*9 + 1*9 = 9*9 = 81. For small numbers this method may not be much quicker than simple addition but certain problems may be greatly simplified.
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