Usual school mathematics can be very practical in our daily life, it enables the serious arithmetic calculation in mind. We will tell You some techniques,
2016-08-30 06:19:53 74
How to multiply in my mind How to multiply a two-digit number in mind As to multiply fast in the mind
the Usual school mathematics can be very practical in everyday life, because it gives the opportunity to conduct serious arithmetic calculation in mind. We will tell You some techniques to help you multiply two-digit numbers quickly without using a calculator or piece of paper and a pen.
it May seem that to multiply in the mind of such large numbers is impossible, but it isn't. There is a way that is understandable even to schoolchildren.
So, for example, take the number 96 and 97.
Calculate the difference of these numbers relative to 100. In this case 3 and 4. Their product is the second part of the solution multiplying numbers 97 and 96 (3*4=12).
the First part is the difference of the first number and the difference of 100 and the second number. In our example this is: 97-4=93.
Thus, we get 97*96 = 93 12
the Essence of this simple and familiar method consists in the decomposition of the multiplier into units and tens. Followed by their successive multiplication. Make it simple, in the mind will have to keep no more than 3 numbers at the same time.
this is the standard way to define a multiplication:
64*86 = (60+4)*(80+6) = 60*80 + 60*6 + 4*80 + 4*6 = 4800 + 360 + 320 + 24 = 5504
But the method is based on 3 actions.
1) Multiply the tens 60 and 80. The result is 4800, remember it.2) Fold works 60*6 80*4. Get 680. Remember this number.3) Multiply units 4*6 = 24 and add up all three numbers. 4800 + 680 +24 = 5504.
See how easy you can multiply in your head!