Month round-up + correctionsSun 27 September1 / 2

September round-up　+　all four costumes

All four costumes of the month, one question each, with different numbers

Name Date

1 · This month's check (5 questions)

Marking is done from the separate answers page, which a parent has. No score is recorded anywhere. Copy only the ones you missed into the corrections notebook.

1Write both the lowest common multiple and the greatest common divisor of 12 and 18.

2²⁄₃ ＋ ¹⁄₆

3Simplify ²⁴⁄₄₀.

4A red lamp flashes every 15 seconds, a blue one every 20. After flashing together, when do they next flash together?

5Which is larger, ⁴⁄₅ or ⁷⁄₉ ?

Month round-up + correctionsSun 27 September2 / 2

September round-up　+　all four costumes

Name Date

2 · This month's costumes — one question from each

6IT — a screen is 2560 by 1600 and their GCD is 320. Find the ratio.

7Machines — gears of 15 and 20 teeth. After how many teeth do they line up again?

8Music — on a 48 cm string, how long is G (length ²⁄₃)?

9Chemistry — fill in　□Al ＋ □O₂ → □Al₂O₃

O comes in 2s on the left and 3s on the right. Same thinking as the gears.

3 · This month's corrections

10Redo anything you missed in part 1. If you got them all, pick the hardest question of September and do that instead.