Take two or three hands-up answers, not open call-outs. Don't settle the glasses question yet — the point is to surface that we can't compare 1.5 and 250 until they share a unit. Hold the litres-vs-ml choice open; it comes back at the wrap.

Suggested Timing

About 8 minutes. Work each step of the ladder live on the board — do not read a script.

Teaching Tips

• 1.5 l → 1,500 ml: ask what a half-litre is in ml before the reveal; five hundred should come back.
• 0.5 l → 500 ml: the leading zero disappears — flag it, because pupils sometimes write 5,000.
• 250 ml → 0.25 l: the reverse direction. Ask which way the digits move now (right), and why (the unit got bigger).

The kg-to-g rule is on the board now, but hold back the explicit link — you want a pupil to name it at the wrap, not you.

Talk this one through together — pupils take turns at the board and the class agrees or corrects out loud. With four conversions across the 10 minutes, that is roughly 2 to 2.5 minutes each including the turn-and-check.

Work each conversion on the ladder together on the board. For each one, get the direction (left or bigger, right or smaller) from the class first. The last one, 75 ml → 0.075 l, is the trickiest — two leading zeros appear. Slow down and let the class read the answer off the ladder before confirming. Circulate the naming: × 1,000 or ÷ 1,000 aloud each time.

This is the practice round — 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: the first three are clean, 3,050 ml → 3.05 l has the awkward internal zero, and 45 ml → 0.045 l is the two-leading-zeros stretch. Before the tricky pair, ask the class to predict how many zeros will sit in front of the digits — then Check.