Three- and four-digit numbers · Usually met around P2
Counting on and back, odd and even, to 10000
After 299 comes 300; before 3000 comes 2999.
How to do it
Method
After 299 comes 300; before 3000 comes 2999
298, 299, 300, 301; 3002, 3001, 3000, 2999
Another way
Find the hundred first
299 + 1 = 300, 300 + 1 = 301
In full
Counting on is 1 more each time; after a 9 in the ones, you carry: after 299 comes 300, because 9 ones and 1 more make 10, the tens are full too, and you get 1 more hundred. Counting back is 1 less each time; from a 0 in the ones you borrow from the place before: just before 3000 comes 2999. 10 more is 1 more in the tens; 100 more is 1 more in the hundreds. Odd or even depends only on the ones: a number ending in 0, 2, 4, 6 or 8 is even, however big it is. Or step along a number line, or count from the nearest hundred or thousand.
Worked examples
Have a go first, then open each one for the answer and the working.
Example 1
6050 is an odd number.
True or false?
Show the answer and working
Answer: False
Look only at the ones digit, 0: 1, 3, 5, 7 or 9 means odd.
Example 2
What number is 10 more than 790?
Show the answer and working
Answer: 800
10 more: 790 + 10 = 800.
Example 3
What number is 10 less than 6152?
Show the answer and working
Answer: 6142
10 less: 6152 − 10 = 6142.
Practise it in the game →Three- and four-digit numbers · Free to start, unlimited questions, no download