Overview
This lesson covers dividing decimal numbers by powers of 10 (10, 100, 1,000) and how to perform these operations, including moving decimal points.
Dividing Decimals by Powers of 10
- To divide a decimal by 10, move the decimal point one place to the left.
- To divide by 100, move the decimal point two places to the left.
- To divide by 1,000, move the decimal point three places to the left.
- The number of zeros in the divisor tells how many places to move the decimal point.
Dividing Decimals by Fractions of 10 (e.g., 1/10, 1/100, 1/1,000)
- To divide a number or decimal by 1/10, 1/100, or 1/1,000, move the decimal point right by 1, 2, or 3 places respectively.
- After moving the decimal, adjust the dividend by adding zeros if needed, then divide as usual.
Sample Problems and Solutions
- Example: 510 ÷ 1/10 = 5,100 ÷ 1 = 5,100.
- Example: 78.46 ÷ 10 = 7.846.
- For word problems, determine what is being divided and use decimal movement to solve.
- Check answers by multiplying the quotient by the divisor for verification.
Mental Division Strategies
- Move the decimal left for whole powers of 10 divisors.
- Move the decimal right for divisors like 1/10, 1/100, or 1/1,000.
Word Problem Solving Steps
- Understand the given numbers and what is being asked.
- Decide on the operation: division.
- Write the number sentence.
- Move the decimal as per the divisor, then compute and check your answer.
Key Terms & Definitions
- Dividend — the number being divided.
- Divisor — the number by which you divide.
- Quotient — the result after division.
- Decimal Point — separates whole numbers from fractional parts.
Action Items / Next Steps
- Complete Learning Tasks 1-4 in your notebook.
- Review decimal movement rules for dividing by powers of 10.
- Practice solving provided sample problems and check your answers.