Show a seven-year-old a box in the middle of a subtraction, like 310 − □ = 244, and you may get a long silence. The box looks like a mistake on the page, not a question. This 2nd grade missing number subtraction worksheet turns that box into a puzzle with a method. At the top, two worked examples walk through 165 − 27 = 138 and 260 − 128 = 132, showing how adding helps undo a subtraction. Below, fifteen sentences from b to p hide one number each, sometimes at the start and sometimes in the middle. Most are 3-digit numbers, with friendly ones like 900 − □ = 200 mixed in. A second page gives the answer key.