Word problems with 3-digit numbers

Word problems with 3-digit numbers

Word problems with 3-digit numbers

A word problem is a tiny story with numbers in it. Your job is to figure out what the story is asking and which calculation answers the question.

A four-step plan

  1. Read the problem twice — slowly.
  2. Find the numbers and underline them.
  3. Decide whether to add or subtract.
  4. Write the calculation, work it out, write the answer.

Words that hint at adding

When the story is about combining or getting more, you usually add:

  • in total / altogether
  • both of them / sum
  • gained / arrived / brought
  • how many in all

Example. The library had 482 books. 156 new books arrived. How many in total?

Plan: combine → add. 482 + 156 = 638.

Words that hint at subtracting

When the story is about removing, comparing or finding what's left, you usually subtract:

  • left / remaining
  • gave away / sold / lost / used
  • how many more (or how many fewer)
  • difference

Example. The bakery baked 540 rolls. By lunch, 287 had been sold. How many were left?

Plan: remove → subtract. 540 − 287 = 253.

Watch out — "more than" can be tricky

"How many more X than Y?" is comparison — you subtract the smaller from the larger.

Tom has 234 stickers. Eva has 158. How many more does Tom have?

Plan: difference → subtract. 234 − 158 = 76.

Two-step problems

Some problems hide two steps. Read carefully — a single calculation might not be enough.

Sam had €500. He spent €185 on shoes and €120 on a jacket. How much does he have left?

Step 1: total spent = 185 + 120 = 305.

Step 2: money left = 500 − 305 = 195.

Write the answer in a sentence

After you compute, write a short sentence that answers the question. Don't leave just a bare number — the question asked for something specific (books, rolls, money…).

Try it

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