Take three hands-up guesses, not open call-outs. Do not work the exact sum yet, the whole point is a rough guess. Write the three guesses on the board so the class can compare them to the estimate later.

3,400: ask which end it is nearer before naming it. Hundreds digit 4, less than halfway, rounds down to 3,000.

6,800: stress it is past the middle. Hundreds digit 8, rounds up to 7,000.

4,500: the make-or-break one. Marker sits exactly halfway. Pause, take a prediction, then reveal the rule: a hundreds digit of 5 always rounds up, so 4,500 becomes 5,000.

Estimate 3,200 + 4,900: no line, work it aloud. 3,200 rounds to 3,000, 4,900 rounds to 5,000, then 3,000 + 5,000 = 8,000. Point out how much quicker than adding the real numbers.

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

For each number, an individual pupil drags the marker onto the correct thousand and says which hundreds digit decided it. Watch for the halfway one, 5,500, listen for pupils reciting five rounds up before they place it. The 4,050 is a low hundreds digit (0), so it rounds down to 4,000, catch anyone tempted to round the tens instead.

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 rounding target the pupil drags the marker to the nearest thousand and presses Check. The final entry is a two-step estimate (round 4,100 → 4,000, round 3,850 → 4,000, add to 8,000). Ask how close do you think our estimate is likely to be, and why? after the last one.