2nd Grade 3-Digit Addition Word Problems Worksheet: Write the Addition Sentence

Tell a seven-year-old that a boy scored 427 points on Friday and 512 on Saturday, and they will want to know who won. Turning that curiosity into math is the whole job of this 2nd grade 3-digit addition word problems worksheet. The page holds three stories. Brooks plays a video game over three days, and three short questions ask which two days to put together. Next, 496 dogs join the 216 already at an animal shelter. Finally, Miss Mary sharpens 87 pencils on Monday and 100 on Tuesday. For each one, your child writes an addition sentence, not just an answer. A second page gives the answer key.

Why the sentence matters more than the sum

In second grade, children start to meet stories where the numbers are too big to picture. With 3-digit numbers, they can no longer draw 427 dots, so they need a sentence that holds the story in a few symbols.

Writing 427 + 129 is that step. It shows which numbers belong together and what to do with them, before any adding happens. The answer key models it clearly, naming each quantity first, then joining the two.

The Brooks story is a smart design for this. It gives three numbers but asks about two days at a time, so your child must choose. In other words, reading carefully becomes part of the math, not a step before it.

At the table: which two days?

Read the Brooks story aloud first, then ask, "Which days does question a talk about?" Let your child underline Saturday and Sunday with a finger before writing.

The usual slip is grabbing the first two numbers in the text, 427 and 512, for every question. If that happens, do not correct it. Instead, ask, "Was Friday in this question?"

The dog problem is shorter, but the word "more" can push a child toward subtracting. Ask, "Are the dogs leaving or arriving?" That one question usually settles it.

For the pencils, 87 + 100 looks odd because one number has only two digits. Point to the hundreds place and talk about it. Line up the ones first.

After the page: stories with big numbers

Big numbers hide in daily life. On a family game night, keep score on paper and add two rounds together with an addition sentence instead of a quick guess. In the car, read two numbers on passing signs and invent a short story that joins them.

For a lighter version, play I Spy with numbers at the grocery store. Spot two prices, then ask your child to tell a tiny story and write the sentence when you get home.

At the end, compare the answers with the key and praise the thinking: "You picked the right two days every time." That shows real reading, not just adding.