Write 4.7 + 0.85 on the board stacked so the right-hand edges line up (so the 7 sits over the 5). Take three hands-up answers, not open call-outs. Listen for a pupil noticing the points don't match up. Don't fix it yet — that is the whole job of Watch and Notice.

First: 4.7 + 0.85 = 5.55. Points under points, tenths above tenths, hundredths above hundredths. 4.7 has an empty hundredths place, fill it as 4.70 so every column has a digit.

Second: 0.3 + 0.27 = 0.57. Same move, 0.3 becomes 0.30. Ask where the zero goes before showing it.

Third: 9.99 + 0.01 = 10.00. Watch the cascade: hundredths make ten and regroup, then tenths, then units, building to a clean ten. Ask what comes next before each column carries.

The trailing zero is the make-or-break move, keep returning to it.

This round is for talking it through together — pupils take turns at the board and the class agrees or corrects out loud.

Let an individual pupil set each addend into the column-addition activity and step the columns. Before each column lands, ask the class to predict any carry. The 0.6 + 0.27 example has the lonely hundredth — watch pupils want to ignore the empty hundredths place; insist that 0.6 gets a placeholder zero (making 0.60). Revoice a good answer: 'so the point keeps everything lined up, and the empty place just gets a zero.'

These are the practice questions — pupils take turns at the board, check each answer, and the class confirms before moving on. Keep the board work brisk rather than over-explaining.

The practice set rises from a clean tenths-only sum up to the cascade-regroup case. Watch for the 9.99 + 0.05 answer — pupils who forget the carry will write 9.104 instead of 10.04. When they slip, point back at the trailing-zero set-up rather than re-teaching from scratch.

Keep this brisk. The trailing-zero habit is the one thing worth restating before pupils move to their activity-book practice.