Hello everyone! Let me share techniques on how to multiply two digit numbers simply by mind, no need for calculator or any sheet of paper and a pen.
Can you mentally find out the answer for 12 x 13 = ____________ in 5 seconds?
In reality you can’t solve for that in 5 seconds. I know the procedure you’re going to use is this:
Can you mentally find out the answer for 12 x 13 = ____________ in 5 seconds?
In reality you can’t solve for that in 5 seconds. I know the procedure you’re going to use is this:
(see Figure 1)
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| Figure 1 |
Did you take only 5 seconds to solve it? Definitely no. So here is mine.
Let me discuss you the procedure. The base here in 12 x 13 is 10. Since 3
in 13 is more than the base add 3 to 12, so we have 15. We already have
the first two digit answer which is 15. One more digit and we will
arrive at the final answer. Multiply 3 in 13 to 2 in 12, we have 2 x 3 =
6. Therefore the answer is 156.
(See Figure 2)
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| Figure 2 |
Let’s have another example different from the first one.
18 x 13 is ___________. We must add in the first place 3 in 13 to 18, the sum is 21. And then multiply 3 to 8, the product is 24. Since the base is 10 the answer should only be in 3 digits. So let’s add them like this:
21
+24
234
We arrived at the answer 234. Try to check to your calculator if the answer is the same. Did you get the same answer? Yes, indeed! Now you can teach your friend, children or anybody techniques on how to multiply two digits number only by mind and takes only seconds to solve.
