Three-digit adding and taking away · Usually met around P2
Giving change
Count up from the price, like a shopkeeper.
How to do it
Method
Count up from the price, like a shopkeeper
$37 → $40 → $100: 3 + 60 = 63
Another way
Column subtraction
100 − 37 = 63
In full
Count up from the price, just like a shopkeeper. A book costs $37 and you pay $100. $37 → $40 is $3, and $40 → $100 is $60. 3 + 60 = 63, so you get $63 change. Paying with $50 works the same way: $28 → $30 is $2, $30 → $50 is $20, 2 + 20 = 22, so $22 change. You can also write 100 − 37 = 63 and use column subtraction with a borrow.
Worked examples
Have a go first, then open each one for the answer and the working.
Example 1
Cap $46, pay $50, change $?
Show the answer and working
Answer: Cap $46, pay $50, change $4
$46, paying $50: count up from the price, $46 → $50 is $4, 46 + 4 = 50, so $4 change
Example 2
Book $41, pay $50, change $?
Show the answer and working
Answer: Book $41, pay $50, change $9
$41, paying $50: count up from the price, $41 → $50 is $9, 41 + 9 = 50, so $9 change
Example 3
Pen $24, pay $50, change $?
Show the answer and working
Answer: Pen $24, pay $50, change $26
$24, paying $50: count up from the price, $24 → $30 is $6, $30 → $50 is $20, 6 + 20 = 26, so $26 change
Practise it in the game →Three-digit adding and taking away · Free to start, unlimited questions, no download