


1. Calculate multiplications of 6,7,8,9 by using your fingers
Did you ever memorize the classic
multiplication table? While calculating multiplications of 15 are
usually easy, when we go to 6 and higher, many of us start to stutter.
This easy method is not taught in most schools, but it’s very quick and
intuitive:

Assign numbers to every finger, the pinky being number
6
and the thumb being number
10
.




If you wish to calculate 7x8 (pictured below), touch the assigned fingers.



The number of fingers below, including the touching fingers, is the tens. (Pictured below,
5
fingers = 5 tens or
50
)




Now, multiply the remainder fingers to find the units. (in the example,
3
fingers multiplied by
2
fingers =
6
)

Add the units to the tens, and you have the result –
56
.



2. Quickly calculate multiplications of 9
To calculate the multiplications of nine, you just need to remember that the
tens increase
and the
units decrease
, and the sum of the total always equals nine.



3. Calculating multiplications of eleven with 2digit numerals

This calculation takes two simple steps:

In the first step, split the digits, then one becomes the hundreds, the other becomes the units.

In the second step, sum the digits and the result becomes the tens.



4. Quickly calculate fractions
Even though fractions are not
something most of us deal with on a daily basis, this method is very
useful, especially for schoolage children.

Turn the multiplication into a
“butterfly” by drawing diagonal ellipses, then multiplying the digits in
each ellipsis. (In the example below,
3x5
and
4x2
)

Write the results down in the appropriate “feeler”.




Multiply the denominators and write it under the butterfly. (In the example,
4x5=20
)

You now have the common denominator
(20), and by adding the two numbers on the top of the butterfly, you
have the numerator. (In our example,
15+8=23
)

You can now simplify the fraction from
to
.




This method also works when you want
to subtract fractions, but to do this, you will need to subtract the
top numbers instead of adding them.
(In our example,
158=7
)



5. Multiplying doubledigit numbers
Multiplication can become harder when
the numbers get bigger, but it doesn’t have to be. This method will
help you get over this, and you’ll find that the larger the number – the
easier it gets:

Subtract 100 from each number.

Add the results, and then subtract it from 100. The result will become the thousands and hundreds digits.

Now multiply the two first results and you’ll get the tens and units.



6. Multiplying double and tripledigit numbers
Another method to multiply
doubledigit numbers is the “line method”, which also works on
multiplying tripledigit numbers. It is vital that you remember to
maintain a lefttoright writing direction, even when drawing the lines:

Begin by drawing diagonal lines to
represent each digit. The other number will be drawn in a crisscross
manner shown in the example below.




Split the drawing into three sections. Each of the three areas represents the hundreds, tens, and units.




Count each crosspoint in each section and write them down one after the other. (Left=
1
, middle=
6
, right=
8
)






To do the same for a tripledigit number, follow the same method, but notice that now you will have 4 sections instead of 3.







7. For kids: How to write “greater than”

Think of the sign as a hungry mouth that always wants to eat the bigger number!

