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To solve this problem, we'll follow these steps:
Step 1: Align the numbers for vertical subtraction.
Step 2: Subtract the digits in the units column.
Step 3: Subtract the digits in the tens column if necessary.
Now, let's work through each step:
Step 1: We'll arrange the numbers as follows:
Step 2: Start by subtracting the digits in the units column: .
Step 3: Move to the tens column: .
The result is 04, which simplifies to just 4.
Therefore, the difference when we subtract 81 from 85 is .
4
\( \begin{aligned} &15 \\ -& \\ &~~4 \\ &\underline{\phantom{776}} & \\ \end{aligned} \)
Lining up numbers vertically ensures you subtract corresponding place values! Units subtract from units, tens from tens. Without proper alignment, you'll subtract the wrong digits and get incorrect answers.
When subtraction gives you zero in the tens place (like 8-8=0), you can drop the leading zero. So 04 becomes simply 4 - this is perfectly correct!
Yes! Always start with the units column (rightmost) and work left. This follows the same pattern as addition and helps avoid confusion with borrowing in harder problems.
Use addition to check subtraction! Add your answer to the number you subtracted: . If you get the original number, your answer is right!
The order matters in subtraction! 85-81=4 (positive), but 81-85=-4 (negative). Always subtract the smaller number from the larger one unless you're working with negative numbers.
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