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## Maths teachers: 60% x 300 = ?

(24 Posts)
wellthereyougo Wed 18-Oct-17 20:21:27

DS is in Year 6 and says this question came up in class today. Now I know that ....

0.6 x 300 = 180
0.6 of 300 = 180
60% of 300 = 180

... but I've never seen it expressed as 60% x 300 before. His teacher says the answer is still 180 (as opposed to 18000% which is what most of them intuitively put in their answer, and probably what I would have put). She also said that this is a new question format they will need to get used to with the new curriculum.

Can any other maths teachers confirm this?

DearTeddyRobinson Wed 18-Oct-17 20:26:10

I'm not a maths teacher but in my day (80s) we were told that 'x' (multiplied by) can be read as 'of' - so when I saw this, I straight away read it as '60% of 300'.

cavatron Wed 18-Oct-17 20:28:22

I teach Year 6 and DearTeddyRobinson is correct. Any time your DS sees X% x .... just read 'of' for 'x'. The curriculum is incredibly intensive now. I never learnt this before I had to teach it!!

Plummer88 Wed 18-Oct-17 20:28:30

It basically means 60% of 300. Just another way of confusing the kids.

My daughter was the first year to sit the new SAT’s and there were two questions worded that way and hey had never been taught it. Good the school is teaching them.

Buildalegohouse Wed 18-Oct-17 20:29:24

Yep. There was a question like this in the 2016 arithmetic sats paper. Mine had never seen it expressed like this and it tripped some of them up.

PurpleDaisies Wed 18-Oct-17 20:31:24

Loads of ours got caught out by it expressed as 60% x 300. Also 1/4 x 150 etc.

wellthereyougo Wed 18-Oct-17 20:32:36

Well yes, I was taught that too, which is why I know 0.6 of 300 = 180.

However, I've never seen it expressed this way before, and it begs the question of what you would write if you really did want to multiply 60% of something by 300. But perhaps that would have to be written as 300(60% of something).

PurpleDaisies Wed 18-Oct-17 20:34:16

It isn't 60% of something x 300, it's just 60% of 300.

PurpleDaisies Wed 18-Oct-17 20:35:54

Sorry, posted by accident.

You would write 60% x something x 300. You could do 60% of 300 first then multiply that by the something because multiplication can be done in any order.

etoiledor Wed 18-Oct-17 20:36:40

Also, 18000% is 18000/100 which is 180, so that answer is also right in a way, it's just that using the % symbol doesn't make sense in this context. So you replace the % symbol with /100 and do the division.

% is not a unit, so 60% x 300 = 18000% would not make sense in the way that 60cm × 300 = 18000cm would make sense.

Teacher needs to go back and make sure they are confident with % as number of parts per hundred and converting % to fraction I think.

mineofuselessinformation Wed 18-Oct-17 20:45:50

The x should really be of IMO. But I'm a bit pedantic about maths.

Cantfindanycement Wed 18-Oct-17 20:48:52

What dearteddy said. But also 18000% is 180, so is correct anyway, it’s just different units (expressed as a percentage not an integer)! I.e 18000 percent = 18000/100= 180 (Per means divide and cent means hundred). Ok, usually things are expressed as percentages between 0 and 1, but unless the question specified the answer should be written as an integer, it’s still correct.

Patchouli666 Wed 18-Oct-17 20:59:56

60 per cent or 60% means 60 over 100
So the sum written fully would be :-

60
---- X 300. = 180
100

MollyHuaCha Wed 18-Oct-17 21:29:00

3 x 4 means 3 ‘lots of’ 4.

60% x 300 means 60 hundredths of 300.

In other words... for every 100, count 60. There are 3 hundreds, so you need three lots of 60.

irvineoneohone Wed 18-Oct-17 22:08:49

Since multiplication is Commutative, it may make more sense if you change order to 300 x 60%.

60% = 0.6 or 6/10 so, 300 x 60% is same as 300 x 0.6 or 300 x 6/10

9toenails Wed 18-Oct-17 22:19:23

I was a maths teacher long ago ...

Yes, as others have said, 'per' means 'divide' (like, for instance, if you want speed in miles per hour, you'll need to divide the number of miles gone by the number of hours taken); and 'of' is 'multiply' (or 'times' if you like that better). [Also remember 'cent' is a hundred (think 'century' or 'centipede' etc.)]

So, '60%x300', same as '60 (divide by 100) times 300'. Or, alternatively, '60%x300', same as '60% of 300'. Answer, either way, 180. (Or, of course, as someone else pointed out, 18000%, which is the same thing, '18000 (divide by 100)', that is, '180' again.)

Summary (useful arithmetic fact): ' PER ' means ' DIVIDE '.

9toenails Wed 18-Oct-17 22:23:34

I was a maths teacher long ago ...

Yes, as others have said, 'per' means 'divide' (like, for instance, if you want speed in miles per hour, you'll need to divide the number of miles gone by the number of hours taken); and 'of' is 'multiply' (or 'times' if you like that better). [Also remember 'cent' is a hundred (think 'century' or 'centipede' etc.)]

So, '60%x300', same as '60 (divide by 100) times 300'. Or, alternatively, '60%x300', same as '60% of 300'. Answer, either way, 180. (Or, of course, as someone else pointed out, 18000%, which is the same thing, '18000 (divide by 100)', that is, '180' again.)

Summary (useful arithmetic fact): ' PER ' means ' DIVIDE '.

irvineoneohone Wed 18-Oct-17 23:03:35

This video explains concept of percent, as 9toe did.
Once dc is secure with the concept, conversion comes automatically.

www.mathantics.com/section/lesson-video/what-are-percentages

Tomorrowillbeachicken Wed 18-Oct-17 23:29:41

Wouldn’t you just times it by 0.6

irvineoneohone Thu 19-Oct-17 00:04:25

@Tomorrow.

I think it's the way the question has been written, 60% x 300, instead of 60% of 300. But yeah, once dc can instantly convert % into fraction or decimal, it will become very clear.

FeedMeAndTellMeImPretty Thu 19-Oct-17 00:23:55

I'm old and not a teacher, but I read it as 'of' and assumed that if you were putting it into a calculator you'd think in your head "60% of 300" and you'd type in '300 x 60 %" You'd see the total of 300x60 first (18000) and then when you press % it would show 180.

catkind Thu 19-Oct-17 00:51:00

60% is just a fraction, another way of writing 60/100 or 0.6. Of course you can multiply a fraction by something. His answer isn't wrong but it isn't as simplified as it should be. Like if someone asks you 60x90 and you write 6x900 as your answer - it's true but you haven't really finished.

Fresta Sat 21-Oct-17 23:09:53

Your dc just need to understand that 60% is the same as 0.6. So 60%x300=0.6x300=180

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