Problem: what number is obtained by adding the units digits of 734 ^ 100 and 347 ^ 83 ?
Rationale: "the units digit of 734 ^ 100 is 6 because 4 raised to the power of an even integer ends in 6 . the units digit of 347 ^ 83 is 3 because powers of 7 end in 7 , 9 , 3 , or 1 cyclically . since 83 is in the form 4 n + 3 , the units digit is 3 . then 6 + 3 = 9 . the answer is c ."
annotated_formula: subtract(subtract(100, 83), divide(100, add(const_1, const_10)))