Word problems present real-world situations requiring addition or subtraction. Understanding the context (joining, removing, comparing) guides students to choose the correct operation and solve meaningfully.
You already know how to add and subtract numbers within 20. Word problems ask you to use those skills in a new way: you have to read a little story, figure out what is happening, and decide which operation fits the situation before you do any calculating.
There are three main kinds of situations in first-grade word problems. The first is *joining*: you start with some amount and more is added. "Tom has 5 marbles and gets 3 more" — the marbles are coming together, so you add. The second is *removing*: you start with some amount and some is taken away. "Tom has 5 marbles and loses 3" — the marbles are being taken out, so you subtract. The third is *comparing*: you have two amounts and want to know the difference. "Tom has 5 marbles and Sam has 3 — how many more does Tom have?" — you subtract to find the gap. Learning to recognize which situation you are in is the most important skill in word problems.
A common mistake is to pick an operation based on a single word rather than the whole story. "More" seems like an addition word, but "how many more does Tom have?" is asking you to compare, which means subtracting. "Left" seems like a subtraction word, but it just means "remaining" — and what remains could be found by adding in some problems. The safe habit is to act out the story in your head: imagine the objects, picture what is happening to them, and ask yourself whether the total is growing or shrinking.
When you set up your number sentence, make sure the order matches the story. In a removal problem, the larger number (what you started with) goes first: 9 - 4, not 4 - 9. In a joining problem, either order works because addition is commutative, but writing it in story order helps you check your work.
After you solve, always ask: does my answer make sense? If Maya started with 9 stickers and gave some away, she should end up with fewer than 9. If your answer is bigger than 9, something went wrong. This kind of checking — reading the answer back into the story — is a habit that will serve you all the way through mathematics.