Concept 7 of 7
Money Word Problems: Buying & Change
Today's big idea
Total the bill first, then take it away from the money handed over to get the change.
Clue words mislead, so following the money beats hunting for the word 'more'.
How it works
👀 What's going on?
You hand over a ₹100 note at the shop and some coins come back. Working out what should come back is a two step job. Most children only do the first step.
💡 Here's the trick
Look at the shop above. Two pencils at ₹15 come to ₹30, and one notebook is ₹40, so the bill is ₹70. Only now does the ₹100 matter: 100 − 70 leaves ₹30 change. Total first, change second.
🪄 How to do it
- 1.In the shop above, note each item's price and how many you buy.
- 2.Multiply each price by its count, then add: that is the total cost.
- 3.If money is handed over, take the total cost away from it.
✍️ Try it
Pens cost ₹12 each. You buy 3 and pay with a ₹50 note. What change do you get? Now a harder one. A bat costs ₹185 and a ball costs ₹65. You pay with three ₹100 notes. What change do you get?
Pens: 3 × 12 = 36, so the bill is ₹36, and the change is 50 − 36 = ₹14. Bat and ball: 185 + 65 = 250, so the bill is ₹250. You handed over 3 × 100 = ₹300, so the change is 300 − 250 = ₹50.
⚠️ Watch out
You might be thinking the word more always means add. Read this one. Riya has ₹120, which is ₹45 more than Sam. Sam has 120 − 45 = ₹75, so more meant subtract. Follow the money, do not hunt for a word.
🌟 Why this matters
Shopping is one long word problem. You do this every time you buy a snack and check what comes back. Hand over too little and you leave without the thing you came for. Working the total before the change is the habit that stops it.
Exam tip: Read the last line of the question again before you answer, because it asks for the change far more often than the total.
Watch me solve one
Quanta solves it
“Watch how I think through one of these — then you try.”
THE PROBLEM
“A pen costs ₹30. Riya buys 3 pens and gives a ₹100 note. How much change does she get?”
- 1
Find total cost
3 pens × ₹30 = ₹90. 🛒
- 2
Spot the clue word
CHANGE → subtract from money paid.
- 3
Subtract
100 − 90 = 10
- 4
Change ✓
Change = ₹10
Now you try one — same steps, different story 👇
See it in action
⚡ Time to play!
Read the clue words, then tap the operation they point to.
PROBLEM 1 OF 3
One pen costs ₹12. You buy 4 pens. What is the total cost?
Which operation?
Quick check
✅ VERIFICATION
Meera buys a water bottle and gets ₹65 change from a ₹200 note. What did the bottle cost?
⚡ Finish the activity above first to answer.
Keep going!