Decimal Operations with Base-Ten Blocks

See decimals as physical blocks. A flat equals 1, a rod equals 0.1, and a small cube equals 0.01. Add, subtract, multiply, and divide by combining and splitting the blocks.

Choose Mode

Choose Operation

Try These Examples

First Number1.24
Flat = 1Rod = 0.1Cube = 0.01
Ones (1)
Tenths (2)
Hundredths (4)
Second Number0.38
Flat = 1Rod = 0.1Cube = 0.01
Tenths (3)
Hundredths (8)
1.24 + 0.38

Decimal Reference

Place Value with Decimals

Each place is 10 times the place to its right.

  • Ones (1) = 10 tenths
  • Tenths (0.1) = 10 hundredths
  • Hundredths (0.01) = smallest here

1.35 = 1 one + 3 tenths + 5 hundredths

Regrouping with Decimals

When adding and the hundredths column reaches 10, regroup:

  • 10 hundredths = 1 tenth
  • 10 tenths = 1 one
  • Same as whole-number carrying, just smaller units

Multiplying Decimals

When multiplying by a whole number, think of repeated addition:

  • 1.2 × 3 = 1.2 + 1.2 + 1.2 = 3.6
  • Count decimal places in each factor
  • The product has the same total decimal places

Dividing Decimals

To divide by a decimal, convert to an equivalent problem with whole numbers:

  • 1.5 ÷ 0.5 = 15 ÷ 5 = 3
  • Multiply both numbers by 10 or 100
  • Then divide as with whole numbers