Read a story problem aloud to a seven-year-old and watch which word they grab first. Very often it is the word more, and the hand reaches for a plus sign before the story is over. This 2nd grade add or subtract stories within 20 worksheet plays with exactly that habit. It opens with Logan’s fish tank: five large fish, fifteen small ones, and two questions that need two different operations. Eight short stories follow, each about two children collecting marbles, where one child collects a few more than the other. Every answer stays within 20, so the thinking goes into the story, not the arithmetic. A second page gives the answer key.