Money is the most natural place to practise grade-3 maths. Every shop receipt is a problem. Every coin purse is a count.
Our examples use US dollars and cents. If you live in the UK, everything carries over directly to pounds and pence — £1 = 100p, and £12.50 is written the same way as $12.50.
Why this matters
Money knits together:
Adding/subtracting (totals, change).
Multiplying (3 items at the same price).
Decimals ($12.50).
Sense-checking ("does $30 for a sandwich seem right?").
These together build financial literacy — a lifelong skill.
Most common mistakes
1. Wrong place value in decimals.
The child writes 5 cents as 0.5</strong>insteadof<strong>0.05.
Fix: always write two digits after the point. "0.05" not "0.5". Read aloud: "zero dollars and five cents".
2. Adding without lining up the points.12.50+3.05 written as 12.50 + 3.5 → wrong.
Fix: always line up the decimal point. Or convert both to cents first, add, then convert back.
3. Mixing cents and dollars.
"5+50cents=55" (wrong — it should be 5 dollars 50 cents = $5.50).
Fix: before adding/subtracting, make units match.
4. Skipping zeros.
"3.5"writteninsteadof"3.50". Same value, but not how prices are written.
Fix: with money, always two digits after the point.
5. Symbol in the wrong place.
"12.50 "insteadof"12.50".
Fix: the dollar (or pound) sign always goes in front; the cent sign goes after: 50¢.
Activities at home
Real shopping. Hand the child a few dollars at the store. They pick a snack and work out their change, counting up like a cashier.
