Meaning of Household Arithmetic

Household Arithmetic is the branch of arithmetic that deals with everyday calculations carried out at home or in domestic life. It includes the simple mathematical processes used in buying and selling, cooking, budgeting, saving, measuring, sharing, and managing resources within the home.

It helps us to make wise decisions on how to spend, save, plan, and use materials efficiently. It is very important for daily living and family management.

1. It helps us to manage money wisely and avoid waste.


2. It helps us to keep proper records of income and expenditure.


3. It helps us to plan family budgets.


4. It helps in determining prices, quantities, and costs of household items.


5. It helps in comparing prices to get the best value for money.


6. It helps in calculating bills, discounts, balances, and change during purchases.


7. It helps us to measure quantities of food, ingredients, fuel, water, etc.


8. It helps in determining time, distances, and rates for daily activities.

1. Shopping and expenditure


2. Household budgeting


3. Cooking and measurement


4. Water and electricity bills


5. Transport and communication


6. Saving and borrowing


7. Record keeping


8. Hire purchase and installment payments


9. Domestic maintenance and repairs

Income and Expenditure: Income refers to all the money received by a person or family, such as salary, wages, allowance, gifts, profits, etc. Expenditure refers to all the money spent on goods, services, and other needs.

Budget: A budget is a plan of how money will be spent or used over a period. It includes expected income and the planned expenses.

Savings: Saving means setting aside part of one’s income for future use. Savings help in emergencies and for future goals.

Record Keeping: This involves keeping written records of money received and spent. Examples: Receipts, invoices, account books, or diaries.

Bills and Payments: Bills are written statements showing money owed for goods or services used. Examples: electricity bill, water bill, school fees bill, etc.

Discount and Change: Discount is a reduction in price. Change is money returned when payment is more than the cost of an item.

Profit and Loss: When you sell something for more than it cost, you make a profit. If you sell for less than it cost, you make a loss.

Hire Purchase and Installment: This means buying an item and paying gradually in parts over time.

1. Total Cost = Unit Price × Quantity


2. Discount = (Discount Rate / 100) × Cost Price


3. Amount after Discount = Cost Price − Discount


4. Profit = Selling Price − Cost Price


5. Loss = Cost Price − Selling Price


6. Percentage Profit = (Profit / Cost Price) × 100%


7. Percentage Loss = (Loss / Cost Price) × 100%


8. Change = Amount Paid − Total Cost


9. Savings = Income − Expenditure

Example 1
Problem: A loaf of bread costs ₦700. If a family buys 5 loaves, how much do they pay?
Solution:
Total cost = ₦700 × 5 = ₦3,500.
Answer: ₦3,500.

Example 2
Problem: A woman’s monthly income is ₦50,000. She spends ₦38,000. How much does she save?
Solution:
Savings = Income − Expenditure = 50,000 − 38,000 = ₦12,000.
Answer: ₦12,000.

Example 3
Problem: Musa buys rice for ₦12,000 and sells it for ₦13,500. Find his profit and percentage profit.
Solution:
Profit = 13,500 − 12,000 = ₦1,500.
Percentage profit = (1,500 ÷ 12,000) × 100 = 12.5%.
Answer: Profit = ₦1,500; Percentage profit = 12.5%.

Example 4
Problem: A student buys an exercise book for ₦350. The seller offers a 10% discount. What is the amount paid?
Solution:
Discount = (10 ÷ 100) × 350 = ₦35.
Amount paid = 350 − 35 = ₦315.
Answer: ₦315.

Example 5
Problem: A man bought a radio on hire purchase. Cash price = ₦18,000. He pays ₦5,000 deposit and 4 monthly installments of ₦4,000 each. Find the total amount paid and extra amount over cash price.
Solution:
Total amount paid = 5,000 + (4 × 4,000) = ₦21,000.
Extra amount = 21,000 − 18,000 = ₦3,000.
Answer: ₦21,000 paid; ₦3,000 extra.

Example 6
Problem: Electricity bill for March is ₦9,500. If payment is delayed and a 5% fine is added, what is the total payment?
Solution:
Fine = (5 ÷ 100) × 9,500 = ₦475.
Total = 9,500 + 475 = ₦9,975.
Answer: ₦9,975.

Example 7
Problem: A family spends ₦25,000 on food, ₦10,000 on transport, ₦5,000 on clothing, and ₦2,000 on electricity. Find total expenditure.
Solution:
Total expenditure = 25,000 + 10,000 + 5,000 + 2,000 = ₦42,000.
Answer: ₦42,000.

Example 8
Problem: A shopkeeper bought goods for ₦20,000 and sold them at a loss of 10%. What was the selling price?
Solution:
Loss = (10 ÷ 100) × 20,000 = ₦2,000.
Selling Price = 20,000 − 2,000 = ₦18,000.
Answer: ₦18,000.

1. Cooking and measurement of ingredients.


2. Shopping and determining total cost, change, and discount.


3. Budgeting and record keeping.


4. Payment of bills and services.


5. Planning family expenses and savings.


6. Comparing prices in the market.


7. Calculating profits or losses in small businesses.


8. Transport and fare estimation.

Common Mistakes Students Make

1. Forgetting to convert percentages to decimals before calculation.


2. Mixing up profit and loss formulas.


3. Wrong subtraction when finding change.


4. Failing to multiply by quantity for total cost.


5. Using selling price instead of cost price when finding percentage profit or loss.

Practice Questions

1. A family buys 6 tins of milk at ₦850 each. How much is the total cost?


2. A trader buys an item for ₦15,000 and sells it for ₦18,000. Find the profit and percentage profit.


3. Calculate the amount to be paid after a 20% discount on ₦25,000.


4. If a family earns ₦70,000 and spends ₦58,000, how much do they save?


5. A gas refill costs ₦12,000. If price increases by 5%, what is the new price?


6. A tailor buys material for ₦5,000 and sells at a loss of 15%. Find his selling price.


7. You paid ₦10,000 for items costing ₦8,750. How much change should you receive?


8. Electricity bill for a month is ₦11,000 with a 7.5% VAT. What is the total payment?

Conclusion

Household Arithmetic is an essential part of daily living. It helps us to manage money, plan our spending, and make informed financial decisions at home and in the office. By learning to calculate cost, profit, savings, discounts, and budgets correctly, we become better at handling money wisely and responsibly.