### Notes on Subtraction
Subtraction is one of the fundamental operations in arithmetic,
representing the process of taking one quantity away from another.
**1. Basic Concepts**
- **Definition:** Subtraction is the operation of finding the difference
between two numbers or quantities. It involves taking away one
number (the subtrahend) from another (the minuend) to get the
result (the difference). citeturn0search0
- **Notation:** The subtraction operation is denoted by the minus sign
(−). For example, in the expression 8 – 3 = 5:
- **Minuend:** 8
- **Subtrahend:** 3
- **Difference:** 5
**2. Properties of Subtraction**
- **Non-Commutative:** Unlike addition, subtraction is not
commutative, meaning that changing the order of the numbers
changes the result. For example, 10 – 5 ≠ 5 – 10.
- **Non-Associative:** Subtraction is also non-associative, which
means that the grouping of numbers affects the outcome. For
instance, (20 – 5) – 3 ≠ 20 – (5 – 3).
**3. Subtraction Methods**
- **Standard Algorithm (Borrowing/Regrouping):** This traditional
method involves aligning numbers by place value and subtracting
each column, borrowing from the next column to the left when
necessary.
- **Counting Up:** Instead of subtracting, one can count up from the
subtrahend to the minuend to find the difference. This method is
often used in making change.
- **Partial Differences:** Subtract each place value separately and then
combine the results. For example, to subtract 652 from 478:
- Subtract hundreds: 600 – 400 = 200
- Subtract tens: 50 – 70 = -20
- Subtract units: 2 – 8 = -6
- Combine: 200 – 20 – 6 = 174
**4. Subtraction of Negative Numbers**
- Subtracting a negative number is equivalent to adding its positive
counterpart. For example, 7 – (−3) = 7 + 3 = 10.
**5. Real-Life Applications**
- **Financial Transactions:** Calculating expenses, determining
change, and balancing accounts.
- **Measurement:** Finding the difference between two
measurements, such as lengths, weights, or temperatures.
- **Time Calculation:** Determining the duration between two time
points.
**6. Practice Problems**
1. Subtract 456 from 789.
2. What is the result of 1000 – 587?
3. If you have $50 and spend $23.75, how much money remains?
For a visual explanation and more examples, you might find this video
helpful:
videoSubtraction – Math | Basic Introductionturn0search2