time yourselfMaths A (spare · mixed review)Tue 29 September1 / 2
September, all of it
A little from everything this month. Finishing early is fine
Name Date
Check it by calculating
1Write both the greatest common divisor and the lowest common multiple of 24 and 36.
25⁄6 ＋ 3⁄10
The answer cancels.
5Which is larger, 7⁄12 or 5⁄9 ?
6Find the lowest common multiple of 4, 6 and 15.
Two at a time is allowed.
Word problems, and putting things in order
7A blue lamp flashes every 18 seconds, a red one every 24. After flashing together, how long until they do so again?
8A ribbon is 5⁄6 m. 1⁄4 m is used, then 1⁄3 m more. How much is left?
You may put all three over one denominator.
9Put 2⁄3, 5⁄8 and 7⁄12 in order, smallest first.
Put all three over one denominator first.
10Two tapes, 48 cm and 72 cm, are cut into equal lengths with nothing left over. Cutting them as long as possible: how long is one piece, and how many pieces are there altogether?
Extra · you may skip thisWhich was the most interesting question you did in September? Say why.
Costume + corrections (spare)Wed 30 September1 / 2
All four September costumes + corrections
One question from each of the four. There are not many different tools inside them
Name Date
September's four costumesIT: screen resolution machines: gears music: string length chemistry: balancing
Today there is one question from each of the four. The last question asks which tool each of them used.
1 · All four costumes
1IT — a photo is 4032 by 3024, and their GCD is 1008. Find the ratio.
2Machines — gears of 14 and 21 teeth. After how many teeth do they line up again, and how many turns has each made?
3Music — on a 72 cm string, how long is F (length 3⁄4)? And G (length 2⁄3)?
4Chemistry — fill in □H₂ ＋ □N₂ → □NH₃
5Which tool did each of questions 1 to 4 use? Choose from "greatest common divisor", "lowest common multiple" and "fractions". One of them comes up twice.
This is the important one today.
2 · September's corrections
6From the corrections notebook, pick two you have not yet done a second time, and do them.
Once you can do a question the second time, that unit is finished.
3 · Looking at October
7October starts with dividing decimals. 1⁄2 written as a decimal is 0.5. What are 3⁄4 and 1⁄5 as decimals?
Fractions and decimals are two ways of writing the same thing.
8Write 0.6 as a fraction, cancelled down.
9Write 1⁄8 as a decimal.
It is 1 ÷ 8.
10Pick the tool you used most in September and write a question of your own that needs it. Write the answer too.