Model Multiplying Two Decimals Less Than One
Modeling the multiplication of two decimals less than one is a Grade 5 math skill in enVision Mathematics, Chapter 4: Use Models and Strategies to Multiply Decimals. Students use a 10×10 grid where each axis represents a decimal less than 1, and the overlapping shaded region shows the product. For example, 0.4 × 0.7 is shown as a 4-by-7 overlap on the grid, giving 28 hundredths or 0.28.
Key Concepts
To multiply two decimals less than one, you can use a 10x10 grid to model the area of a rectangle. The product of the two decimals is represented by the overlapping shaded area.
Common Questions
How do you model multiplying two decimals less than one?
Use a 10×10 grid where one decimal shades columns and the other shades rows. The overlapping shaded squares represent the product.
What does 0.3 × 0.5 look like on a grid?
Shade 3 columns for 0.3 and 5 rows for 0.5; the overlap is 15 squares out of 100, so 0.3 × 0.5 = 0.15.
Why is the product of two decimals less than one smaller than either factor?
Both factors are less than 1, so you are taking a fraction of a fraction, resulting in a smaller portion.
Where is modeling decimal multiplication taught in enVision Grade 5?
Chapter 4: Use Models and Strategies to Multiply Decimals in enVision Mathematics, Grade 5.
What math concept does a 10×10 grid show for decimal multiplication?
It shows an area model: length times width equals area, applied to decimals, making the abstract multiplication visual and concrete.