Subtraction

Subtraction is the mathematical operation of taking away some numbers from other numbers to find the amount that is left. It provides an easy way to calculate remaining quantities in daily life, such as determining the change due after making a purchase or counting how many objects remain after some are removed.

Subtracting with fingers

• Fingers provide a simple counting tool when subtracting quantities that are ten or smaller.
• In a bakery, a customer purchases a single cake priced at five rupees and hands over a ten-rupee note.
• Ten fingers represent the ten rupees received from the customer before any cost is removed.
• Counting backwards by five fingers leaves five fingers standing.
• The baker subtracts five from ten to give five rupees of change back to the customer.

Calculation method for larger numbers

When working with numbers larger than ten, human hands do not have enough fingers to count the whole amount, so a written calculation method is needed. For example, if a boy living in a forest collects fifteen bananas for breakfast and a monkey secretly takes away three of them, the math problem is fifteen minus three. The calculation begins with the first set of digits on the right, which is five minus three, resulting in two. Next, the digit one on the left has no number beneath it, so taking away zero from one leaves one, giving the boy a final total of twelve bananas.

Applying subtraction to everyday problems

• Subtraction helps determine the final amount left over whenever items are shared, sold, or taken away.
• In a home example, a kitchen has a starting supply of eighteen fresh apples.
• A mother notices the large number of apples and gives seven of them away to the neighbours.
• The remaining count of apples in the house is found by subtracting seven from eighteen.
• Using the calculation method helps find the exact number of apples that are still left at home.