Problem: what is the last digit of 13 ^ 35 ?
Rationale: "explanation : let ’ s begin by looking for a pattern as we increase the exponent . 13 ^ 1 = 13 ( units digit is 3 ) 13 ^ 2 = 169 ( units digit is 9 ) 13 ^ 3 = 2197 ( units digit is 7 ) notice that a nice pattern emerges . we get : 3 - 9 - 7 - 1 - 3 - 9 - 7 - 1 - 3 - 9 - 7 - 1 - … whenever n is a multiple of 4 , the units digit of 13 ^ n is 1 the units digit of 13 ^ 35 is 7 answer is b"
annotated_formula: multiply(floor(divide(power(const_10, 13), 35)), 35)