Multiplication Tricks || Sum of unit digit is 10 and remaining digits are same

Let n3 and n7 is a number where n is an integer.

STEP 1:First we have to check,sum of unit is 10 and remaining digit is same.

STEP 2: $ n \times (n+1)$ which gives the left hand side answer.

STEP 3: Multiply unit digit of the given number which gives the right hand side answer.

Combing the STEP 1 output and STEP 2 output we will get the final result.

In General,

$(n3) \times (n7)= \underparen { \quad n \times (n+1) \\ \text{LHS ANSWER}}$ $ \qquad \underparen {\qquad 3\times 7 \\ \text{RHS ANSWER}}$

Example 1: Find $37 \times 33 $?

STEP 1: Here n=3, $3 \times (3+1) =12$ [LHS ANSWER]

STEP 2: $ 3 \times 7 =21 $ [RHS ANSWER]

STEP 3: Combining the STEP 1 and STEP 2 together we will get our final result i.e 1221

Example 2: Find $72 \times 78 $?

STEP 1: Here n=7, $7 \times (7+1) =56$ [LHS ANSWER]

STEP 2: $ 2 \times 8 =16 $ [RHS ANSWER]

STEP 3: Combining the STEP 1 and STEP 2 together we will get our final result i.e 5616

Example 3: Find $104 \times 106 $?

STEP 1: Here n=10, $10 \times (10+1) =110$ [LHS ANSWER]

STEP 2: $ 4 \times 6 =24 $ [RHS ANSWER]

STEP 3: Combining the STEP 1 and STEP 2 together we will get our final result i.e 11024