A problem where more are added
A jar has 24 counters. Then 3 more counters are dropped in. How many counters are there now?
Start with 24, then add 3 more. 24 + 3 = 27, so there are 27 counters now.
Year 2
Solve problems with addition and subtraction using concrete objects and pictorial representations
Use objects, picture models and short number sentences to decide whether to add or subtract in a one-step problem.
Lesson overview
Number - addition and subtraction
A story problem becomes easier when we show it clearly. We can draw the amounts with tens rods and ones cubes, then think about what changed. If more are added, we add. If some are taken away, we subtract.
A problem where some are taken away
Ben has 36 stickers. He gives 4 stickers away. How many stickers does he have left?
Start with 36, then take away 4. 36 - 4 = 32, so Ben has 32 stickers left.
A picture model can show both parts
There are 21 red beads and 15 blue beads. How many beads are there altogether?
We combine the two groups because we want the total. 21 + 15 = 36.
Worked example
Mia has 42 shells. She finds 6 more shells on the beach. How many shells does she have now?
- Read the story and notice that Mia gets more shells.
- Start with 42.
- Add 6 more.
- 42 + 6 = 48.
- So Mia has 48 shells now.
Try it
Read the short problem, then decide whether to add or subtract.
Question 1
Question 2
Question 3
Question 4
Question 5
Common mistakes
These are the slips to watch for when reading one-step story problems.
- Choosing subtraction when the story says more are being added.
- Choosing addition when the story says some are being taken away.
- Skipping the picture or number sentence and guessing from the words.
Related topics
These ideas support choosing the right operation and showing it clearly.
- Add and subtract numbers using concrete objects, pictorial representations, and mentally.
- Add and subtract numbers using concrete objects and pictorial representations, including two two-digit numbers.
- Recognise and use the inverse relationship between addition and subtraction and use this to check calculations and solve missing number problems.