You are given a math word problem and you are supposed to apply a single mathematical operators like addition, subtraction, multiplication or division on the numbers embedded in the text to answer the following question and then only report final the numerical answer.

Lizette has 813 stamps . Lizette has 125 more stamps than Minerva . How many stamps does Minerva have ?
688

Each CD rack holds 8 CDs . A shelf can hold 4 racks . How many total CDs can fit on the shelf ?
32

Sam has 86 yellow and 20 green marbles . Joan took 25 of Sam 's yellow marbles . How many yellow marbles does Sam now have ?
61