Understand decimal place values and learn to read and write decimals correctly. Master the relationship between decimals and fractions through visual models.
Scenario: You're exploring a decimal grid! A 10×10 grid represents one whole, where each small square represents 0.01 (one hundredth). You need to color 0.3 of the grid and 0.45 of another grid. How many squares should you color in each?
This activity will help you understand that decimals are just another way to write fractions, and that the decimal point separates the whole number part from the fractional part.
Decimals use place values just like whole numbers, but they extend to the right of the decimal point.
Decimals and fractions represent the same values, just in different forms.
The decimal point separates the whole number part from the fractional part. Everything to the left is a whole number, everything to the right is less than one.
Example: In 3.45, the 3 is the whole number part, and .45 is the fractional part (45 hundredths).
Read the whole number part first, then say "and" for the decimal point, then read the decimal part as if it were a whole number, followed by the place value.
Example: 0.45 is read as "zero and forty-five hundredths" or "forty-five hundredths"
Use decimal grids to visualize decimals. A 10×10 grid represents 1 whole, where each row is 0.1 and each small square is 0.01.
Example: To show 0.3, color 3 rows (30 squares). To show 0.45, color 4 complete rows plus 5 squares in the 5th row.
Practice with decimal grids:
Practice reading decimals:
1. How do you read 0.6?
2. How do you read 0.23?
3. How do you read 1.8?
4. How do you read 2.45?
5. Write "five tenths" as a decimal
6. Write "thirty-two hundredths" as a decimal
7. Write "three and four tenths" as a decimal
8. Write "one and seventy-five hundredths" as a decimal
9. Convert 3/10 to a decimal
10. Convert 7/100 to a decimal
11. Convert 0.9 to a fraction
12. Convert 0.64 to a fraction
Wrong: 0.45 is read as "forty-five" (missing the place value)
Correct: 0.45 is read as "forty-five hundredths"
Wrong: Thinking 0.3 means 3 hundredths
Correct: 0.3 means 3 tenths (the 3 is in the tenths place)
Decimals use place values that extend to the right of the decimal point
The decimal point separates whole numbers from fractional parts
Decimals and fractions represent the same values in different forms
Visual models like decimal grids help understand decimal concepts