Here’s an example of a SPEED MATH shortcut for MULTIPLYING NUMBERS WITH LAST DIGIT SUM 10: (Mul) S10dx from the MULTIPLICATION category.

When can I use this method?
For multiplying any 2-digit number with another 2-digit number such that the sum of the last digits of the multiplier and multiplicand = 10 and the remaining digits of multiplier are same as that of the multiplicand.
For multiplying any 3-digit number with another 3-digit number such that the sum of the last digits of the multiplier and multiplicand = 10 and the remaining digits of multiplier are same as that of the multiplicand.
You cannot use this method to multiply numbers with unequal number of digits, i.e. multiplying a 2-digit number with a 3-digit number.
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