Adding and subtracting · Year 5
In Year 5 you learn: numbers with more than 4 digits.
Adding puts amounts together; subtracting takes away or finds the difference between two amounts. They are opposites: one undoes the other, so every subtraction can be checked with an addition. Good mental strategies (counting on, partitioning, using bonds) make both quick and reliable.
Key facts
- Adding can be done in any order: 7 + 5 = 5 + 7. Subtracting cannot.
- Partition to add: 47 + 35 = 40 + 30 + 7 + 5 = 82.
- Find a difference by counting up from the smaller number.
- Fact family: if 46 + 37 = 83 then 83 − 37 = 46 and 83 − 46 = 37.
- Check a subtraction by adding the answer back on.
- Look for pairs that make 10 or 100 when adding three numbers.
Worked examples
Example 1
64 − 28
Answer: 36
Example 2
A train leaves with 52 passengers. 17 get off and 9 get on. How many are on now?
Answer: 44
Example 3
Kilimanjaro is 5,895 m high and Mont Blanc is 4,806 m high. How much higher is Kilimanjaro?
Answer: 1,089 m