Lab
Drag a split on a bond, a number line, or an area rectangle. Ask “How did you see it?” There is no quiz until you start a round.
1. See the groups
Name the split you see — rows of five, a ten and leftovers. Counting by ones is a trap, not the answer.
2. Friendly numbers
Jump to 10, 100, or 1 on an open number line. Compensation keeps the value the same.
3. Break apart
Multiply with an area model. Partial products on the rectangle, not a stacked algorithm.
4. Bar first
Part-whole or comparison — pick the picture before the number. “More” is not a secret code for add.
5. Stretch
Two-step bars, bigger area, or hundredths on a 10×10 grid.
Ten items per level. Two tries, then Why. Teachers can stay in Lab all period.