We already know one half really well. Picture a strip shaded to one half, and beside it the very same length cut into ten equal pieces with five of them shaded. So here is our puzzle for today: if we know one half, what would its decimal twin look like — the decimal, written with a decimal point, that names the very same amount?

This shows how everyday fractions match decimals. Each fraction is shaded on a strip lined up against a strip cut into ten equal pieces called tenths. One tenth shaded is written 0.1, so we can read the decimal straight off the board: one half reaches the same point as 0.5, one fifth as 0.2. Watch where each shaded edge lands.

We shade these fractions on the board together and say each one's decimal twin: one half, then one tenth, then one quarter. As we shade the tenths strip we will also step it up to three tenths, so we can read off 0.1 and 0.3. Each time, we read off both names — the fraction and the decimal — and check the shaded amount is the same either way. Everyone follows the board and calls out the decimal twin with us.

Today we shade these amounts in order and match each to its decimal: 0.1, then 0.5, then 0.3, and finally 0.25. The last one is the sneaky one: one quarter lands between two tenths, so watch carefully how far you shade before you check it.