find the ones digit of 73 ^ 320
"cyclicity of 3 is 3,9 , 7,1 after 4 multiplication again the cycle repeats . so divide 320 by 4 and we get 87 as quotient and 2 as remainder . so cycle will run for 87 times and then 2 times more . so pick up the 2 nd item from the cycle . hence answer d ."
subtract(power(subtract(73, multiply(add(const_3, const_4), const_10)), subtract(320, multiply(floor(divide(320, const_4)), const_4))), multiply(const_2, const_10))