Mental Math Tricks Play with 9, 99,999..
Many students math can be nightmare. The attitude towards the maths will change this scary figure. Feel always that Maths is simple and easy. Yes maths is fun and it is easy if you apply our mind. I have listed below few mental tricks to hopefully improve your general knowledge of maths and it will help you speed up when you need to do math in your mind.
When you do multiply by 9, or 99, or 999 or even 9999...
Multiply by 9 is really multiplying by 10-1. Anybody notice this? Yes. It is true. So, 9×9 is just 9x(10-1) which is 9×10-9 which is 90-9 or 81. Let’s try for a harder sample: 46×9 = 46×10-46 = 460-46 = 414. One more test: 68×9 = 680-68 = 612. And Whenever you multiply by 99, you multiply by 100-1. I will put this into another way that A×99 is as above explained A×100-A thats all. So any, 46×99 = 46x(100-1) = 4600-46 = 4554. Also same way Multiplying by 999 is similar to multiplying by 9 and by 99. 38×999 = 38x(1000-1) = 38000-38 = 37962. This practice will help everyone improve the mental calculation of every maths activities.
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