Today you will be learning another amazing shortcut to multiply 2 numbers whose difference is 2.This trick is especially effective to use when the number in between the 2 numbers to be multiplied is 5.You will see why.
Shortcut to multiply any 2 numbers whose difference is 2
Let us go through the steps
Step 1:Identify the number in between the 2 numbers.
Step 2:Find the square of the number identified in step 1.
Step 3:Subtract 1 from the result obtained in step 2.
Let us now consider few examples to understand better
Example 1:12 x 14=?
Notice that there is difference of 2 between the numbers 12 and 14.
We shall now apply the trick that we learnt
Step 1:We find that 13 lies in between 12 and 14.
Step 2:Squaring 13 we get
13²=169
Step 3:Subtracting 1 from the result obtained in step 2
We get 169 -1=168
Ans 12 x 14=168
Example 2: 24 x 26=?
Step 1: We find that 25 lies in between 24 and 26.
Step 2: Squaring 25 we get
25²=625
(Use the shortcut trick to square any number ending in 5)
Step 3:Subtracting 1 from the result obtained in step 2
We get 625 -1=624
Ans 24 x 26=624
Example 3: 27 x 29=?
Step 1: We find that 28 lies in between 27 and 29.
Step 2: Squaring 28 we get
28²=784
Step 3:Subtracting 1 from the result obtained in step 2
We get 784 -1=783
Ans 27 x 29=783
Example 4: 17 x 19=?
Step 1: We find that 18 lies in between 17 and 19.
Step 2: Squaring 18 we get
18²=324
Step 3:Subtracting 1 from the result obtained in step 2
We get 324 -1=323
Ans 17 x 19=323
Example 5: 16 x 18=?
Step 1: We find that 17 lies in between 16 and 18.
Step 2: Squaring 18 we get
17²=289
Step 3:Subtracting 1 from the result obtained in step 2
We get 289-1=288
Ans 16 x 18=288
Tip: This trick is most effective to use when you know square of the number in between the 2 numbers.