Sunday 29 May 2016

Maths tips and tricks

The 12 Times Table


Please select row & column its easy
For Instance, Row 10 and Column 5 = 10X5 = 50 you can do easily

What About the 12 Times Table?

Sounds tough, but once you have mastered the 10× table, it is just a few steps away.
Firstly, 11× is mostly easy: from 11×2 to 11×9 you just put the two digits together. 11×2=22, 11×3=33, ..., 11×9=99.
And of course 2×, 5× and 10× just follow their simple rules you know already, so it just leaves these to remember:
  • 3×12=36,
  • 4×12=48,
  • 6×12=72,
  • 7×12=84,
  • 8×12=96,
  • 9×12=108
And the "Big 3":
  • 11×11=121,
  • 11×12=132 and
  • 12×12=144

Tricks by Number

to multiply
by
Trick
2
add the number to itself (example 2×9 = 9+9)
5
the last digit goes 5, 0, 5, 0, ...
is always half of 10× (Example: 5x6 = half of 10x6 = half of 60 = 30)
is half the number times 10 (Example: 5x6 = 10x3 = 30)
6
when you multiply 6 by an even number, they both end in the same digit.
Example: 6×2=12, 6×4=24, 6×6=36, etc
9
the last digit goes 9, 8, 7, 6, ...

your hands can help! Example: to multiply 9 by 8, hold your 8th finger down, and count "7" and "2", the answer is 72
is 10× the number minus the number. Example: 9×6 = 10×66 = 60−6 = 54
when you add the answer's digits together, you get 9.
Example: 9×5=45 and 4+5=9. (But not with 9×11=99)
10
put a zero after it
11
up to 9x11: just repeat the digit (Example: 4x11 = 44)
for 10x11 to 18x11: write the sum of the digits between the digits
Example: 15x11 = 1(1+5)5 = 165
Note: this works for any two-digit number, but when the sum of the digits is more than 9, we need to"carry the one". Example: 75x11 = 7(7+5)5 = 7(12)5 = 825.
12
is 10× plus 2×


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