The same blocks with new names: a flat is now 1 whole, a rod is a tenth and a small cube is a hundredth. Ten of one still make one of the next.
🧱 Place Value →0.0 ≠ 1.4
Use + and − under each column.
0.0
When a column gets to 10, swap them for 1 block in the next column to the left.
Each place after the point is worth a tenth of the place before it. In 3.47 the 3 is worth 3, the 4 is worth 0.4 (four tenths) and the 7 is worth 0.07 (seven hundredths).
Children already know that ten of one block make one of the next. Calling the flat 1 makes the rod a tenth and the small cube a hundredth, so decimals follow the same rule instead of feeling like new maths.
0.5 is 5 tenths: five rods. 0.45 is 4 rods and 5 small cubes, which is less. Building both with blocks shows it at once, and it helps with the common mistake of thinking a longer decimal is bigger.
Tenths usually come at about 8 or 9 and hundredths at about 9 or 10, alongside money, measuring and percentages.