Multiplying by doubling and halving


There are cases when you’re multiplying two numbers together and one of the numbers is even. In this case you can divide that number by two and multiply the other number by 2. You can do this over and over until you get to multiplication this is easy for you to do.


Let’s say you want to multiply 14 by 16. You can do this:

14×16 = 28×8 = 56×4 = 112×2 = 224.

Again, 12×15 = 6×30 = 6×3 with a 0 at the end so it’s 180.

48×17 = 24×34 = 12×68 = 6×136 = 3×272 = 816.



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3 comments

  1. Nice trick, I'm amaze to see this trick and it's too easy to solve it. I would like to share a resource for students to find the math tutors. http://www.selectmytutor.co.uk/subject-maths.html

    ReplyDelete

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