Example : 32 * 11
Step 1 : Split 32 apart, i.e. : 3__2
Step 2 : Add the two digits of the number together 3 + 2 = 5
Step 3 : Place the answer, 5 in between 3__2
Step 4 : 352.(It’s the final answer)
Multiply By 9, 99, 999…
Example 1 : 45 * 99
Step 1 : 45 -1 = 44
Step 2 : Complement of 45 = (100 – 45) = 55
Step 3 : Append the values of Step 1 & 2.
Step 4 : 4455 (It’s the final answer)
Square of any number ending with 5
Example 1 : 85*85 = 7225
Step 1 : Last 2 digits of the result will always be = 25
Step 2 : First 2 digits will be 8*9 = 72 (i.e. multiply the first digit with immediate higher number )
Step 3 : 7225 (It’s the final answer)
Please try :
55 * 55
35 * 35
Multiply Numbers Close to 100
Example 1 : 88*98 = 8624
Step 1 : Both 88 and 98 are close to 100.
Step 2 : 88 is 12 below 100 and 98 is 2 below 100
Step 3 : As 88 and 98 are less than 100 so do minus
Step 4 : LHS of the ans = 100 – (12+2) = 86
Step 5 : RHS of the ans = 12*2 = 24
Step 6 : LHS|RHS = 8624 (It’s the final answer)
Example 2 : 103*104 = 10712
Step 1 : Both 103 and 104 are close to 100.
Step 2 : 103 is 3 above 100 and 104 is 4 above 100
Step 3 : As 103 & 104 are more than 100 so, do add
Step 4 : LHS of the result = 100 + (3+4) = 107
Step 5 : RHS of the result = 3*4 = 12
Step 6 : LHS|RHS = 10712 (It’s the final answer)
Multiply any even number by 5
Example 1 : 4 x 5 =
Step 1 : Take the number being multiplied by 5 and cut it in half, this makes the number 4 become the number 2.
Step 2 : Multiply the output of step 1 by 10 .
Step 3 : 20 (It’s the final answer)