Same Math › Grades 4–5 › Decimal grids
What is a decimal grid?
A decimal grid is a square split into 100 small squares. The whole grid is 1, each column is one tenth, and each small square is one hundredth. Shading squares shows a decimal.
- The whole grid is 1. Each column is a tenth.
- Each small square is a hundredth. 37 are shaded.
- 3 tenths and 7 hundredths: 0.37 = 37/100
Why schools teach it
It connects decimals to fractions kids already know
Fourth graders learn that 3/10 is the same as 30/100 (4.NF.C.5) and write fractions with denominators of 10 or 100 as decimals (4.NF.C.6). The grid shows both at once: three columns cover exactly 30 squares.
It also stops a classic mistake. Many kids think 0.5 is smaller than 0.37 because 5 is less than 37. On the grid, 0.5 is half the square, far more than 37 small squares.
At the kitchen table
What to say, and what to skip
Say this
How many small squares are shaded?
How many full columns? So how many tenths?
Which is more, 0.5 or 0.37? Show me on the grid.
How would you write that as a fraction?
37 out of 100 squares is 37/100.
Skip this
- Reading 0.37 as "point thirty-seven."Classes teach "thirty-seven hundredths" because it says the value.
The longer decimal is bigger.
0.5 is more than 0.37. The grid shows why.- Skipping fractions and going straight to decimals.The fraction link is what 4th grade is building.
See it in action
Showing 0.6 and 0.06 on grids
0.6 is 6 tenths: shade 6 full columns
60 small squares0.06 is 6 hundredths: shade 6 small squares
6 small squaresCompare the two grids
0.6 is ten times 0.06
Seeing 60 squares next to 6 makes the zero after the decimal point mean something.
Free practice sheet
Make a decimal grid sheet
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Fridge cheat sheets
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Parents also ask
What is a tenths grid?
A square split into 10 columns only. Each column is 0.1. It's used before the hundredths grid.
How do grids show 1.25?
Two grids: one fully shaded (1) and 25 squares of the second (0.25).
Is a grid the same as base-ten blocks?
Very close. In 4th grade a flat can stand for 1, a rod for 0.1 and a cube for 0.01.
Why do kids think 0.5 < 0.37?
They compare 5 and 37 as whole numbers. Shading both on a grid fixes it quickly.