Hi! Welcome to another five minute class of Glad2teach. Hey before we start this class, tell me something honestly. Did you try to impress somebody with these amazing tricks? I am sure you must have. So here is another piping hot treat for you straight out of the oven.
Can you mentally find out what is 13x12 in three seconds status? I know that you can. So give it a try. Your time starts now. Your time is over. Well, if your answer was 156 then that's terrific because you are calculating faster than the calculator.
In case, you could not calculate at all, not to worry. For you know that in next four minutes you will be able to multiply any numbers closer to base ten in less than three seconds. So let's see the usual view of multiplying 13 with 12. So two three times is 6, two one times is two, one three times is three, one one times is one. Now add the numbers in the column. So 6, 3+2 is 5 and this is 1. I know you must be getting impatient. You must be saying that cut this harder way. I am already sicken tired of it, show me the smarter way.
So here is your smarter way. The smarter way of multiplying 13 with 12 is the same base method of multiplication that we learnt in the last class and yes, you guessed it right. The base here is ten. So since 12 is 2 more than the base, so add this 2 that is this digit to this entire number 13+2 is, correct 15 and since base ten has one zero, so there is one place more to go, three two times is six and that's your answer. Isn't that simple. You bet it is.
So let's take one more example and this time you try to solve it. There you go. What is 13x13? So first thing you did was to add this 3 to this entire number. 13 + 3 is 16 and three three times is nine. So the answer is 169. Isn't that simple, right.
So let's take one more example and be careful this time because I am going to set up a trap for you. What is -- let's say 16 x 12. So add this 2 to 16, 16 + 2 is 18. Now six two times is 12 and you know that 12 is a two digit number, so and there is only one place here to go. So carry forward 1 write 2 here, so the answer is 192. Isn't it. So this way -- see these are very common operations, no matter what question of mathematics you are trying to solve, you have to multiply the numbers. So if you know these techniques then you will be able to multiply quickly and correctly.
So before we end this class, let me give you one last example. What is let's say 18x14? So first thing, add this 4 to 18, 18+4 is 22, right. So eight four times is 32, so carry forward 3 write 2 here. 22+3 is 25, so the answer is 252. That's your answer. Isn't it simple. So see you next time with plenty more such cool tips and tricks. Bye-bye.
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