Step-by-step Maths Level 1: Counting forwards and backwards to 20
Part of the Step-by-step Maths Level 1 counting to 20 chapter. Chapter overview · whole chapter on one page
Counting forwards and backwards to 20
Counting forwards means going up one at a time: 12, 13, 14.
Counting backwards means going down one at a time: 14, 13, 12.
The number after is one more. The number before is one less.
Key ideas
- Counting forwards: one more each time.
- Counting backwards: one less each time.
- The number after 9 is 10.
- The number before 10 is 9.
Method. One more means the next number when we count on.
- Start at the number. We begin where we are.14
- Count on one. Say the number that comes next.14 + 1 = 15
- Write the answer. 15
Check. Count back one: 15 take away 1 is 14. It works.
Watch out. One more is the next number, not the same number.
Method. One less means the number just before when we count back.
- Start at the number. We begin where we are.15
- Count back one. Say the number that comes just before.15 - 1 = 14
- Write the answer. 14
Check. Count on one: 14 add 1 is 15. It works.
Watch out. One less is the number before, not the number after.
Method. Count back one at a time from 17.
- Look at the numbers. Each number is one less than the one before.17, 16, __, 14
- Count back one. After 16 comes 15 when we count back.16 - 1 = 15
- Write the answer. 15
Check. Count on from 14: 14, 15, 16, 17. It works.
Watch out. Count back one step at a time.
Watch out
Watch out. When you count backwards, the numbers get smaller. Do not count up by mistake.
Exam tip
Grown-up tip. Count up and down with your child on a stairs, a bus or a wall chart. Start at any number, not always at 1. Ask: “What comes next?”
Exercise 2A Counting forwards and backwards
Non-calculatorMethod. One more means the next number when we count on.
- Start at the number. We begin where we are.11
- Count on one. Say the number that comes next.11 + 1 = 12
- Write the answer. 12
Check. Count back one: 12 take away 1 is 11. It works.
Watch out. One more is the next number, not the same number.
Method. One less means the number just before when we count back.
- Start at the number. We begin where we are.6
- Count back one. Say the number that comes just before.6 - 1 = 5
- Write the answer. 5
Check. Count on one: 5 add 1 is 6. It works.
Watch out. One less is the number before, not the number after.
Method. Count in steps of one. Say the numbers in order, then fill the gap.
- Look at the numbers in order. Find the numbers next to the gap.5, 4, __, 2
- Count one step at a time. Counting back means one less each time.5, 4, 3, 2
- Write the missing number. 3
Check. Say the whole line out loud. Every number is one more or one less than the one before. ✓
Watch out. Go one step at a time. Do not skip a number.
Method. Count in steps of one. Say the numbers in order, then fill the gap.
- Look at the numbers in order. Find the numbers next to the gap.4, 5, 6, __, 8
- Count one step at a time. Counting on means one more each time.4, 5, 6, 7, 8
- Write the missing number. 7
Check. Say the whole line out loud. Every number is one more or one less than the one before. ✓
Watch out. Go one step at a time. Do not skip a number.
Method. One more means the next number when we count on.
- Start at the number. We begin where we are.19
- Count on one. Say the number that comes next.19 + 1 = 20
- Write the answer. 20
Check. Count back one: 20 take away 1 is 19. It works.
Watch out. One more is the next number, not the same number.
Method. One less means the number just before when we count back.
- Start at the number. We begin where we are.5
- Count back one. Say the number that comes just before.5 - 1 = 4
- Write the answer. 4
Check. Count on one: 4 add 1 is 5. It works.
Watch out. One less is the number before, not the number after.
Method. Count in steps of one. Say the numbers in order, then fill the gap.
- Look at the numbers in order. Find the numbers next to the gap.15, 14, __, 12
- Count one step at a time. Counting back means one less each time.15, 14, 13, 12
- Write the missing number. 13
Check. Say the whole line out loud. Every number is one more or one less than the one before. ✓
Watch out. Go one step at a time. Do not skip a number.
Method. Count in steps of one. Say the numbers in order, then fill the gap.
- Look at the numbers in order. Find the numbers next to the gap.9, 10, 11, __, 13
- Count one step at a time. Counting on means one more each time.9, 10, 11, 12, 13
- Write the missing number. 12
Check. Say the whole line out loud. Every number is one more or one less than the one before. ✓
Watch out. Go one step at a time. Do not skip a number.
Method. One more means the next number when we count on.
- Start at the number. We begin where we are.4
- Count on one. Say the number that comes next.4 + 1 = 5
- Write the answer. 5
Check. Count back one: 5 take away 1 is 4. It works.
Watch out. One more is the next number, not the same number.
Method. One less means the number just before when we count back.
- Start at the number. We begin where we are.19
- Count back one. Say the number that comes just before.19 - 1 = 18
- Write the answer. 18
Check. Count on one: 18 add 1 is 19. It works.
Watch out. One less is the number before, not the number after.
Method. Count in steps of one. Say the numbers in order, then fill the gap.
- Look at the numbers in order. Find the numbers next to the gap.7, 6, __, 4
- Count one step at a time. Counting back means one less each time.7, 6, 5, 4
- Write the missing number. 5
Check. Say the whole line out loud. Every number is one more or one less than the one before. ✓
Watch out. Go one step at a time. Do not skip a number.
Method. Count in steps of one. Say the numbers in order, then fill the gap.
- Look at the numbers in order. Find the numbers next to the gap.8, 9, 10, __, 12
- Count one step at a time. Counting on means one more each time.8, 9, 10, 11, 12
- Write the missing number. 11
Check. Say the whole line out loud. Every number is one more or one less than the one before. ✓
Watch out. Go one step at a time. Do not skip a number.
Method. One more means the next number when we count on.
- Start at the number. We begin where we are.1
- Count on one. Say the number that comes next.1 + 1 = 2
- Write the answer. 2
Check. Count back one: 2 take away 1 is 1. It works.
Watch out. One more is the next number, not the same number.
Method. One less means the number just before when we count back.
- Start at the number. We begin where we are.17
- Count back one. Say the number that comes just before.17 - 1 = 16
- Write the answer. 16
Check. Count on one: 16 add 1 is 17. It works.
Watch out. One less is the number before, not the number after.
Method. Count in steps of one. Say the numbers in order, then fill the gap.
- Look at the numbers in order. Find the numbers next to the gap.17, 16, __, 14
- Count one step at a time. Counting back means one less each time.17, 16, 15, 14
- Write the missing number. 15
Check. Say the whole line out loud. Every number is one more or one less than the one before. ✓
Watch out. Go one step at a time. Do not skip a number.
Method. Count in steps of one. Say the numbers in order, then fill the gap.
- Look at the numbers in order. Find the numbers next to the gap.10, 11, 12, __, 14
- Count one step at a time. Counting on means one more each time.10, 11, 12, 13, 14
- Write the missing number. 13
Check. Say the whole line out loud. Every number is one more or one less than the one before. ✓
Watch out. Go one step at a time. Do not skip a number.