Three- and four-digit numbers · Usually met around P2
Skip counting in 4s, 6s, 7s, 8s, 9s, 20s, 25s, 50s and more
Add the same each time; four 25s make 100.
How to do it
Method
Add the same each time; four 25s make 100
250, 500, 750, 1000
Another way
Jumps on a number line
0 → 25 → 50 → 75 → 100
In full
Counting in 20s is adding 20 each time: 20, 40, 60, 80, 100. In 25s: 25, 50, 75, 100 — four 25s make 100. In 50s: 50, 100, 150, 200. Counting in 200s, 250s, 500s and 1000s works the same, just bigger: 250, 500, 750, 1000. Counting in 4s, 6s, 7s, 8s or 9s is adding the same number each time too: 7, 14, 21, 28, 35 is how the days of weeks add up. Learn the first few, then spot the pattern: counting in 25s, the last two digits only go 25, 50, 75, 00 in turn. Or make jumps of the same size along a number line; counting back takes the same number away each time.
Worked examples
Have a go first, then open each one for the answer and the working.
Example 1
Count in 25s: 75, 100, □, 150
Show the answer and working
Answer: 125
25 more each time: 100 + 25 = 125.
Example 2
Count back in 4s: 48, □, □, 36
Fill in each box
Show the answer and working
Answer: 44，40
4 less each time: 48, 44, 40, 36.
Example 3
What does this list count in? 50, 75, 100, 125
- A. 250
- B. 20
- C. 50
- D. 25
Choose the right answer
Show the answer and working
Answer: D. 25
Neighbours differ by 75 − 50 = 25, so it counts in 25s.
Practise it in the game →Three- and four-digit numbers · Free to start, unlimited questions, no download