Math · Unit 2

Adding and Subtracting

Addition, subtraction, number bonds and simple sums

Addition and subtraction are one relationship viewed from two directions, and learning them together is much faster than learning them separately.

The unit covers number bonds to ten, adding and taking away, carrying into larger numbers, and the word problems where the real skill is working out which operation the situation calls for.

This unit breaks down into 21 short steps and 120 questions, starting at difficulty 1 and building to 2. Below you can see exactly what it covers, how the path is structured, and worked examples with explanations.

Steps: 21
Questions: 120
Difficulty: 1-2

What this unit covers

Taking Away
Everyday Sums
Adding Numbers
Adding Bigger Numbers
Number Bonds to 10

Where this fits

Follows Counting and Numbers. Times Tables and Sharing extends the same logic to multiplication.

Where people slip

Subtraction is not commutative. Order matters, and mixing that up with addition - where it does not - causes a large share of early arithmetic errors.

How the unit is structured

Adding and Subtracting runs as 21 short steps that unlock in order. 15 are practice rounds and 6 are challenge rounds that pull together everything before them. Questions start at difficulty 1 and climb to 2 as you progress.

Step 1 · easierStep 21 · harder

Challenge rounds

Example questions

30 real questions from this unit, with the answer and the reason behind it, grouped by what they practise. There are 120 in the unit altogether.

Adding Bigger Numbers

Choose all that applyLevel 2
1. Which sums equal 50? Pick all that are right.
- 35 + 15correct
- 20 + 30correct
- 25 + 20
- 40 + 15
35 + 15 and 20 + 30 both make 50.
Fact or fibLevel 2
2. 25 + 25 = 50.
Answer: True
Yes, 25 and 25 more make 50.
Fill the blankLevel 2
3. 45 + 30 = ____
- 75correct
- 74
- 85
- 15
45 and 30 more make 75.
Guess the numberLevel 2
4. A library has 64 books on one shelf and 28 on another. How many books are there in total?
Answer: 92 books
64 books and 28 more make 92.
Match the pairsLevel 2
5. Match each sum to its answer.
Answer: 22 + 7 = 29; 31 + 6 = 37; 44 + 5 = 49
22 + 7 = 29, 31 + 6 = 37, and 44 + 5 = 49.
Multiple choiceLevel 2
6. What is 34 + 25?
- 59correct
- 58
- 60
- 49
34 and 25 more make 59.

Adding Numbers

Build the sentenceLevel 1
7. Build a true addition sentence.
Answer: Eight plus five equals thirteen
8 + 5 = 13, so eight plus five equals thirteen.
Choose all that applyLevel 1
8. Which sums equal 7? Pick all that are right.
- 3 + 4correct
- 5 + 2correct
- 4 + 4
- 6 + 3
3 + 4 and 5 + 2 both make 7.
Fill the blankLevel 1
9. 2 + 6 = ____
- 8correct
- 7
- 9
- 4
2 and 6 more makes 8.
Match the pairsLevel 1
10. Match each sum to its answer.
Answer: 2 + 3 = 5; 4 + 4 = 8; 6 + 3 = 9
2 + 3 = 5, 4 + 4 = 8, and 6 + 3 = 9.
Multiple choiceLevel 1
11. What is 5 + 5?
- 10correct
- 9
- 11
- 15
5 and 5 more makes 10.
Fact or fibLevel 2
12. 28 + 14 = 42.
Answer: True
Yes, 28 and 14 more make 42.

Everyday Sums

Build the sentenceLevel 1
13. Build a true sentence about the apples.
Answer: Two apples and three apples make five apples
2 + 3 = 5, so two apples and three apples make five apples.
Choose all that applyLevel 1
14. A basket has 3 red apples and 4 green apples. Which are true? Pick all that are right.
- There are 7 apples in allcorrect
- There is 1 more green apple than redcorrect
- There are 5 apples in all
- There are more red apples than green
There are 7 apples in all, and 1 more green than red.
Fact or fibLevel 1
15. If you eat 2 of your 6 grapes, you have 4 grapes left.
Answer: True
Yes, 6 take away 2 leaves 4.
Fill the blankLevel 1
16. Leo reads 8 pages, then 7 more. He read ____ pages in all.
- 15correct
- 14
- 16
- 1
8 pages and 7 more make 15.
Guess the numberLevel 1
17. A box has 7 crayons. You add 6 more crayons. How many crayons are in the box now?
Answer: 13 crayons
7 crayons and 6 more make 13.
Multiple choiceLevel 2
18. A shop had 40 apples. It sold 18 and then got 12 more. How many apples now?
- 34correct
- 33
- 35
- 70
40 take away 18 is 22, then add 12 to make 34.

Number Bonds to 10

Build the sentenceLevel 1
19. Build a true number bond sentence.
Answer: Four and six make ten
4 + 6 = 10, so four and six make ten.
Choose all that applyLevel 1
20. Which pairs make 10? Pick all that are right.
- 6 + 4correct
- 3 + 7correct
- 5 + 4
- 8 + 3
6 + 4 and 3 + 7 are both bonds to 10.
Fact or fibLevel 1
21. 6 + 4 = 10.
Answer: True
Yes, 6 and 4 are a bond that makes 10.
Fill the blankLevel 2
22. 16 + ____ = 20
- 4correct
- 3
- 5
- 6
16 and 4 are a bond that makes 20.
Match the pairsLevel 2
23. Match each sum to its answer.
Answer: 12 + 8 = 20; 11 + 6 = 17; 9 + 5 = 14
12 + 8 = 20, 11 + 6 = 17, and 9 + 5 = 14.
Multiple choiceLevel 2
24. Which number completes the bond to 20: 13 + ____ = 20?
- 7correct
- 6
- 8
- 17
13 and 7 make 20.

Taking Away

Fact or fibLevel 1
25. 10 - 2 = 7.
Answer: False
Not quite, 10 take away 2 is 8.
Multiple choiceLevel 1
26. What is 9 - 6?
- 3correct
- 2
- 4
- 15
Take 6 away from 9 and 3 is left.
Choose all that applyLevel 2
27. Which subtractions equal 8? Pick all that are right.
- 15 - 7correct
- 12 - 4correct
- 14 - 5
- 11 - 2
15 - 7 and 12 - 4 both make 8.
Fill the blankLevel 2
28. 12 - 5 = ____
- 7correct
- 6
- 8
- 17
12 take away 5 leaves 7.
Match the pairsLevel 2
29. Match each subtraction to its answer.
Answer: 44 - 19 = 25; 52 - 18 = 34; 61 - 28 = 33
44 - 19 = 25, 52 - 18 = 34, and 61 - 28 = 33.
Odd one outLevel 2
30. Which one does NOT equal 7?
- 16 - 8correct
- 15 - 8
- 13 - 6
- 10 - 3
16 - 8 makes 8, but the others all make 7.

Where these questions come from. Each unit starts as a plan of the concepts it should cover and the difficulty it should span. Questions are written against that plan with AI assistance, then checked by a validator that rejects anything without a single defensible answer, an explanation, or plausible wrong options. How we write questions sets out the whole process, and corrections are fixed in the bank and reach the site and the app the same day.

How you practise

This unit mixes 14 different question formats, so you are recalling and applying rather than recognising the same layout every time.

Build the sentence
Choose all that apply
Fact or fib
Fill the blank
Guess the number
Match the pairs
Multiple choice
Odd one out
Picture question
Put in order
Sort into groups
Spell it
True or false
Type the answer

Practise Adding and Subtracting

120 questions across 21 steps. Start with step one and crawl at your own pace.

Play this unit

Read about Adding and Subtracting

Explainers from our blog on what this unit covers. Each one ends with real questions from the bank.

What Is Infinity? Why Some Infinities Are Bigger Than OthersInfinity is not a very large number but a property of collections that never run out. How Cantor tamed it, and why the points on a line outnumber the integers.September 14, 2026 · 5 min read

More units in Math

See all 18 units in Math →