calculate the l . c . m of 4 / 9 , 5 / 7 , 9 / 13 , 7 / 15 is :
"required l . c . m = l . c . m . of 4 , 5 , 9 , 7 / h . c . f . of 9 , 7 , 13 , 15 = 1260 / 1 = 1260 answer is c"
multiply(multiply(4, 5), multiply(9, 7))