Solve Decimal Multiplication: 7.81 × 10 Step by Step

Q: Why does multiplying by 10 move the decimal point right?

Multiplying by 10 makes numbers 10 times larger! Moving the decimal point right increases place values: ones become tens, tenths become ones, etc.

Q: What if there aren't enough digits after moving the decimal?

Add zeros as needed! For example, $ 3.2 \times 10 = 32.0 $ or simply 32. The zero shows the decimal moved correctly.

Q: How do I remember which direction to move the decimal?

Multiplying by 10, 100, 1000 = move decimal RIGHT. Dividing by 10, 100, 1000 = move decimal LEFT. Think: multiply = bigger = move right!

Q: What happens when I multiply by 100 or 1000?

Move the decimal point one place for each zero! So $ 7.81 \times 100 = 781 $ (2 places right) and $ 7.81 \times 1000 = 7810 $ (3 places right).

Q: Can I use this trick with any decimal number?

Yes! This method works for any decimal number multiplied by powers of 10 (10, 100, 1000, etc.). Just count the zeros and move the decimal that many places right.

Decimal Multiplication with Powers of Ten

$7.81\times10=$

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Step-by-step video solution

Watch the teacher solve the problem with clear explanations

00:00 Solve

00:04 According to the number of zeros, move the decimal point

00:09 Move the decimal point as many places as zeros

00:16 And this is the solution to the question

Step-by-step written solution

Follow each step carefully to understand the complete solution

Understand the problem

$7.81\times10=$

Step-by-step solution

To solve this problem, we'll follow these steps:

Step 1: Identify the given number and confirm it is 7.81.
Step 2: Understand that to multiply by 10, we move the decimal point one place to the right.
Step 3: Perform the operation and identify the resulting number.

Now, let's work through each step:

Step 1: We start with the decimal number $7.81$ .

Step 2: To multiply by 10, move the decimal point one position to the right:

$7.81$ becomes $78.1$ when multiplied by 10.

Step 3: Thus, the final result of multiplying $7.81 \times 10$ is $78.1$ .

Therefore, the solution to the problem is $78.1$ .

Final Answer

$78.1$

Key Points to Remember

Essential concepts to master this topic

Rule: Multiplying by 10 moves decimal point one place right
Technique: $7.81$ becomes $78.1$ when decimal shifts right
Check: Count decimal places: original has 2, result has 1 place ✓

Common Mistakes

Avoid these frequent errors

Moving decimal point the wrong direction
Don't move the decimal point left when multiplying by 10 = getting 0.781! This makes the number smaller instead of larger. Always move the decimal point RIGHT when multiplying by powers of 10.

Practice Quiz

Test your knowledge with interactive questions

$\text{0}.07\times10=$

FAQ

Everything you need to know about this question

Why does multiplying by 10 move the decimal point right?

Multiplying by 10 makes numbers 10 times larger! Moving the decimal point right increases place values: ones become tens, tenths become ones, etc.

What if there aren't enough digits after moving the decimal?

Add zeros as needed! For example, $3.2 \times 10 = 32.0$ or simply 32. The zero shows the decimal moved correctly.

How do I remember which direction to move the decimal?

Multiplying by 10, 100, 1000 = move decimal RIGHT. Dividing by 10, 100, 1000 = move decimal LEFT. Think: multiply = bigger = move right!

What happens when I multiply by 100 or 1000?

Move the decimal point one place for each zero! So $7.81 \times 100 = 781$ (2 places right) and $7.81 \times 1000 = 7810$ (3 places right).

Can I use this trick with any decimal number?

Yes! This method works for any decimal number multiplied by powers of 10 (10, 100, 1000, etc.). Just count the zeros and move the decimal that many places right.

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