GRADE 8 Mathematics MEASUREMENTS – Money Notes
Mathematics — MEASUREMENTS: Money (Kenya) — Age 13
Money is a unit used to measure value. In Kenya the currency is the Kenyan shilling (KSh). Use these notes to learn how to read, add, subtract, multiply and compare money amounts.
Coins
KSh 1 · KSh 5 · KSh 10 · KSh 20
Banknotes
KSh 50 · KSh 100 · KSh 200 · KSh 500 · KSh 1,000
Small units
1 shilling = 100 cents (cents are rare now). Write cents as decimals: KSh 12.50 = 12 shillings 50 cents.
1. Writing money amounts
Use KSh before the amount: KSh 120 or KSh 12.50. You can write shillings and cents as:
- KSh 25.00 (25 shillings)
- KSh 7.50 (7 shillings and 50 cents)
- KSh 0.75 (75 cents → less than one shilling)
2. Adding and subtracting money
When adding or subtracting, line up the decimal points (like normal decimals).
Example 1 — Add:
Price of notebook = KSh 45.75
Price of pen = KSh 12.50
Total = KSh 45.75 + KSh 12.50 = KSh 58.25
Price of pen = KSh 12.50
Total = KSh 45.75 + KSh 12.50 = KSh 58.25
Example 2 — Subtract (Change):
You pay KSh 200 for items costing KSh 137.40.
Change = KSh 200.00 − KSh 137.40 = KSh 62.60
Change = KSh 200.00 − KSh 137.40 = KSh 62.60
3. Multiplying and dividing
Use multiplication when many items have the same price. Use division to find unit price or to split money.
Example 3 — Multiplication:
4 packets of maize flour cost KSh 58.25 each.
Total = 4 × KSh 58.25 = KSh 233.00
Total = 4 × KSh 58.25 = KSh 233.00
Example 4 — Division (unit price):
KSh 360 buys 6 kg of rice. Unit price = KSh 360 ÷ 6 = KSh 60 per kg.
4. Comparing prices (best buy)
Find the unit price (price per item or per kg) and compare.
Example 5:
- Packet A: 2 kg for KSh 240 → unit price = 240 ÷ 2 = KSh 120/kg
- Packet B: 5 kg for KSh 550 → unit price = 550 ÷ 5 = KSh 110/kg
Best buy: Packet B (cheaper per kg).
- Packet B: 5 kg for KSh 550 → unit price = 550 ÷ 5 = KSh 110/kg
Best buy: Packet B (cheaper per kg).
5. Money and decimals — quick rules
- Always line up decimals when adding and subtracting.
- Two decimal places show cents: KSh 12.5 → write KSh 12.50.
- When multiplying, carry out normal multiplication, then place the decimal so the result has the sum of decimal places from the factors (or use a calculator).
6. Word problems (with worked answers)
Q1: Jane buys 3 sweets at KSh 8.50 each and a juice at KSh 25.00. How much did she spend?
Working: 3 × 8.50 = 25.50; 25.50 + 25.00 = KSh 50.50.
Answer: KSh 50.50
Working: 3 × 8.50 = 25.50; 25.50 + 25.00 = KSh 50.50.
Answer: KSh 50.50
Q2: A matatu fare is KSh 50. If you travel 3 times in a week and pay daily, how much do you spend?
Working: 3 × 50 = KSh 150.
Answer: KSh 150
Working: 3 × 50 = KSh 150.
Answer: KSh 150
7. Practice — try these
- Add: KSh 32.75 + KSh 17.45 = ?
- Subtract: KSh 500 − KSh 263.80 = ?
- Multiply: 7 notebooks at KSh 24.30 each. Total = ?
- Compare: Which is cheaper per litre — 2 L for KSh 180 or 3 L for KSh 250?
- If a kilo of tomatoes is KSh 95, how much for 2.5 kg?
Answers (click to reveal)
1) KSh 50.20
2) KSh 236.20
3) 7 × 24.30 = KSh 170.10
4) 2 L → 180 ÷ 2 = KSh 90/L; 3 L → 250 ÷ 3 ≈ KSh 83.33/L → 3 L pack is cheaper per litre.
5) 2.5 × 95 = KSh 237.50
2) KSh 236.20
3) 7 × 24.30 = KSh 170.10
4) 2 L → 180 ÷ 2 = KSh 90/L; 3 L → 250 ÷ 3 ≈ KSh 83.33/L → 3 L pack is cheaper per litre.
5) 2.5 × 95 = KSh 237.50
8. Tips for everyday use
- Carry a small notebook or use phone calculator to keep track of totals when shopping.
- Round prices when estimating quickly (e.g., KSh 47 ≈ KSh 50) and then adjust.
- Always check receipts and count change carefully.
Note: This guide uses Kenyan shillings (KSh). Some small cents coins are now rare, so most transactions are in whole shillings or shillings with a decimal (e.g., KSh 12.50).