Grade 4 Mathematics Numbers – Addition Notes
Mathematics — Numbers
Subtopic: Addition (for age 9, Kenya)
What is Addition?
Addition is joining two or more numbers to find the total. The sign for addition is + (plus). Example: 7 + 5 = 12 (seven added to five gives twelve).
Everyday example (Kenyan context)
A matatu fare is KSh 30. If you travel twice, you pay 30 + 30 = KSh 60. Adding helps us find totals of money, people, or objects.
Number line method (visual)
Example: 3 + 4 — start at 3, jump 4 steps to the right
0
1
2
3
→ → → →
4
5
6
7
Result: 3 + 4 = 7
Using place value (tens and ones) — visual blocks
Example: 24 + 13
24 (2 tens, 4 ones)
10
10
1
1
1
1
13 (1 ten, 3 ones)
10
1
1
1
Combine tens and ones
Tens: 10 + 10 + 10 = 30
Ones: 1+1+1+1+1+1+1 = 7 → Total = 30 + 7 = 37
Answer: 24 + 13 = 37
Vertical addition with carry (step-by-step)
Example: 58 + 67
| carry: 1 | . |
| 58 | |
| +67 | 125 |
Steps:
- Add ones: 8 + 7 = 15 → write 5 in ones, carry 1 to tens.
- Add tens: 5 + 6 = 11, plus carry 1 gives 12 → write 12 in tens → 125.
Rules and tips
- Commutative: a + b = b + a (e.g., 6 + 9 = 9 + 6).
- Associative: (a + b) + c = a + (b + c) (helps when adding many numbers).
- When adding many numbers, group tens and ones to make adding easier.
- Check with subtraction: total − one addend = the other addend.
Word problems (Kenya examples)
1) A teacher brings 45 exercise books and then buys 32 more. How many books now?
Solution: 45 + 32 = 77 books.
2) At the market, Mary buys fruits: 18 oranges and 27 mangoes. How many fruits?
Solution: 18 + 27 = 45 fruits.
3) Bus fare is KSh 20. If you take the bus 3 times, how much do you pay?
Solution: 20 + 20 + 20 = KSh 60.
Practice questions
- 12 + 9 = ?
- 47 + 25 = ?
- 59 + 36 = ?
- 103 + 89 = ?
- Musa collected 24 bottle caps, Anna collected 17. How many together?
- One textbook costs KSh 80. If you buy 2, how much do you pay?
- 8 + 7 + 5 = ? (use grouping)
- 234 + 56 = ? (vertical method)
- 76 + 44 = ?
- 150 + 75 = ?
Answers
- 21
- 72
- 95
- 192
- 41
- KSh 160
- 20 (group as 8+7=15, 15+5=20)
- 290
- 120
- 225