Look at this number written on the board: 0.001.

How many of these tiny amounts do you think we would need to make one whole? And how could we be sure we are right?

Each chart shows a number with its digits already placed in the columns: units, tenths, hundredths, thousandths. Notice which column every digit is in, and keep an eye on any zeros.

Today we build decimals together on the place-value chart. The columns are units, tenths, hundredths and thousandths. When a number is called, we place each digit in its column and then read the whole decimal back aloud, checking each column as we go.

Today we build decimals with place-value blocks. The columns are still units, tenths, hundredths and thousandths, but each digit is that many blocks in its column. An empty column means zero blocks there, and the zero holds the place.

Work one together first: 0.305.

• 3 blocks in the tenths column
• no blocks in the hundredths column (the zero holds this place)
• 5 blocks in the thousandths column

Check the live total reads 0.305, then say it aloud: three tenths and five thousandths.

Now build these on the interactive and press Check: 0.006, then 0.05, then 0.408, then 1.207, then 3.09. The zeros catch people out, so say each one aloud before you check.

What we learned today

• The three columns to the right of the point are tenths, hundredths and thousandths.
• Each column to the right is ten times smaller than the one before it.
• A zero in a decimal column holds the place so the other digits stay in their correct columns.

Coming up

Next we will use base-ten blocks to model thousandths, so you can see and hold how much smaller each column really gets.