Finger multiplication
The use of finger multiplication has been widespread through the years. It is not the traditional way of doing multiplication
in school today.
However, if your kid has trouble remembering the whole multiplication table, multiplication with fingers is a good alternative
To multiply with fingers, you are only required to remember the multiplication table up to 5 × 5.
After that, all multiplication can be performed with your fingers
Here is the technique:
The two numbers to be multiplied are each represented on a different hand
Each hand may have some raised fingers and some closed fingers at the same time
Number of fingers to raise = Factor − 5. Remember that a factor is a number in a multiplication problem
The sum of the raised fingers is the number of tens
The product of the closed fingers is the number of ones
Example #1:
7 × 8
For 7, use your left hand and raise 2 fingers (Factor − 5 = 7 − 5 = 2) .
This means there are 3 closed fingers
For 8, use your right hand and raise 3 fingers.
This means that there are 2 closed fingers
Sum of raised fingers = 2 + 3 = 5. This means we have 5 tens or 50
Product of closed fingers = 3 × 2 = 6.
This means that we have 6 ones
50 + 6 = 56
Example #2:
9 × 6
For 9, use your right hand and raise 4 fingers.
This means there is 1 closed finger
For 6, use your left hand and raise 1 finger.
This means that there are 4 closed fingers
Sum of raised fingers = 4 + 1 = 5. This means we have 5 tens or 50
Product of closed fingers = 1 × 4 = 4.
This means that we have 4 ones
50 + 4 = 54
Example #3:
8 × 5
For 8, use your left hand and raise 3 fingers.
This means there are 2 closed fingers
For 5, use your left hand and raise no finger.
This means that there are 5 closed fingers
Sum of raised fingers = 3 + 0 = 3.
This means we have 3 tens or 30
Product of closed fingers = 2 × 5 = 10.
This means that we have 10 ones or 1 ten or 10
30 + 10 = 40

Jul 03, 20 09:51 AM
factoring trinomials (ax^2 + bx + c ) when a is equal to 1 is the goal of this lesson.
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