When we count on, we start at a number and say the next numbers in order. After 9 comes 10, after 19 comes 20, and after 99 comes 100. The ones go up from 0 to 9, then the tens go up by one.
We can also count back. Counting back means each number is one less: 45, 44, 43. Counting on and back helps us add and take away later.
Worked example
What number comes next? 97, 98, 99, …
- The numbers go up by 1 each time.
- After 99 the ones start again at 0 and we get a new hundred.
Answer:100
Key words
- count on
- say the numbers that come next
- count back
- say the numbers that come before
- order
- the right place in a list
Practise this
New questions every time.
Common Core-referenced: 1.NBT.A.1