Lesson: Subtracting Within 1,000

Objective

Learn how to subtract numbers within 1,000 using various strategies.

Understanding Subtraction

Subtraction is the process of finding the difference between two numbers. The general form is:

$$A - B = C$$

Where:

• $A$ is the minuend (the number from which another number is subtracted),
• $B$ is the subtrahend (the number that is to be subtracted), and
• $C$ is the difference.

Steps for Subtracting Within 1,000

1. Align the numbers vertically by their place values.
2. Subtract starting from the rightmost digit (the ones place) to the left.
3. If the top digit is smaller than the bottom digit, borrow from the next place value.
4. Write the answer below the line.

Example

Let's subtract $456$ from $823$:

   823
- 456
-----

1. Start with the ones place: $3 - 6$. We cannot do this, so we borrow $1$ from $2$ (making it $1$) and add $10$ to $3$ (making it $13$).
   • Now, $13 - 6 = 7$.
2. Move to the tens place: $1 - 5$. Again, we cannot do this. We borrow $1$ from $8$ (making it $7$) and add $10$ to $1$ (making it $11$).
   • Now, $11 - 5 = 6$.
3. Finally, the hundreds place: $7 - 4 = 3$.

So, the final answer is:

   823
- 456
-----
   367

Key Questions

• What is the minuend and subtrahend in a subtraction problem?
• How do you manage borrowing in subtraction?
• Can you solve $700 - 345$ using the steps provided?

Practice Problems

1. $912 - 478 = ?$
2. $605 - 289 = ?$
3. $850 - 423 = ?$

Keywords

• Subtracting
• Minuend
• Subtrahend
• Difference
• Borrowing
• Place Value