how many integerskgreater than 100 and less than 700 are there such that if the hundreds and the units digits ofkare reversed , the resulting integer is k + 99 ?
"numbers will be like 102 = > 201 = 102 + 99 203 = > 302 = 103 + 99 so the hundereth digit and units digit are consecutive where unit digit is bigger than hundred digit . there will be five pairs of such numbers for every pair there will 10 numbers like for 12 = > 102 , 112,132 , 142,152 , 162,172 , 182,192 . total = 5 * 10 = 50 hence a ."
add(multiply(divide(100, const_10), multiply(const_2, const_4)), divide(100, const_10))