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

[EX Q]: the music room has 27 violins . there are also 15 flutes . 18 students are in the school band . how many instruments are in the music room ?
[EX A]: 42

[EX Q]: for the walls of the house he would use 9 large planks of wood . if each plank of wood needs 8 pieces of nails to be secured how many nails does john need for the house wall ?
[EX A]: 72

[EX Q]: isabel had 90 ds games . if she gave 87 to her friend how many would she have left ?
[EX A]:
3