Take three hands-up estimates first, then ask where a trade might happen. Do not work the sum yet, keep this as estimating and spotting a possible trade only. Give five seconds of quiet think-time before any hands go up.

1,256 + 1,323 = 2,579. Brisk. No trade: 6+3=9, 5+2=7, 2+3=5, 1+1=2. Establish the right-to-left habit and move on.

2,475 + 1,168 = 3,643. Units 5+8=13, say ten and three, 3 stays, 1 ten carries. Tens 7+6=13 plus 1 is 14, 4 stays, 1 hundred carries. Two trades in a row.

3,608 + 2,196 = 5,804. Take the prediction first: will a trade reach the thousands? Then work it. Units 8+6=14, write 4 carry 1. Tens 0+9=9 plus 1 is 10, write 0 carry 1. Hundreds 6+1+1=8. Thousands 3+2=5. Stops at 8 hundreds, so no. Check who predicted right.

4,857 + 3,265 = 8,122. The key one, give it most time. Units 7+5=12 carry 1. Tens 5+6+1=12 carry 1. Hundreds 8+2+1=11, 1 thousand carries. Thousands 4+3+1=8. Trace the carry rippling through every column.

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

Call one sum at a time and send a different pupil up for each. The board tool starts on 2,134 + 1,523; re-enter each next pair on the tool as you move to it, so the interactive shows the sum the class is working. Insist on right-to-left working: units first, and say the carry aloud (ten and three, carry one). Watch for the common slip of adding the carry into the wrong column. On 5,678 + 2,456, pause the class to predict where the trade will reach before the pupil finishes the hundreds column.

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.

For each problem, ask which words tell us to add before working the sum. Watch for the trade reaching the thousands on the last two. Ask which of these needs a trade all the way to the thousands column? as the class predicts before checking.