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## Answers

1) just multiply the rightmost digits of the two numbers and the digit in the right of the answer will be the rightmost digit of the total multiplication.

FOR EG: HERE THE TWO NO.S CONTAIN 7 AS THEIR RIGHTMOST DIGITS SO MULTIPLY THEM I.E. 7*7=49 HERE NOW THE DIGIT PRESENT IN THE RIGHT OF THE RESULTANT I.E 9 WILL BE THE RIGHT MOST DIGIT OF 17*17

(10+7)∧17

it forms (x + y)∧n

use binomial expansion

(x+y)*n = Nc0x∧n.y∧0 +Nc1x∧n-1.y∧1...................Ncnx∧0.b∧n

= 17C010∧17.7∧0 +17C1 10∧16.7∧1 +.............................. 17c1710∧0.7∧17

thus the right most digit start with 49 approximately so it proves that last of the digit will be 9

so right digit is 9