# Talk

## 109.50 divided by 1.46 - how are you supposed to work this out

(10 Posts)

if you're 10 yo?

InternetFOREVER Wed 26-Mar-14 18:06:52

I think maths has changed since I was at school - do they still learn long division? If I was doing it I'd take out the decimal points, and do long division on it as whole numbers, would make it simpler to me at least. Does it follow on from what they were doing in lessons?

noblegiraffe Wed 26-Mar-14 18:10:18

With a calculator.

(Maths teacher!)

TarkaTheOtter Wed 26-Mar-14 18:12:40

Long division.
They can multiply both by 100 if the decimal is confusing.

Khara Wed 26-Mar-14 18:15:36

Yep - multiply both by 100 to remove decimal and then chunk!

Khara Wed 26-Mar-14 18:24:19

So:
10950 / 146

10950
-7300 (50 x 146)
-----
3650
-2920 (20 x 146)
-----
730
-730 (5 x 146)
--
0

50 + 20 + 5 = 75

Khara Wed 26-Mar-14 18:25:48

Easy

fizzly Wed 26-Mar-14 21:43:33

Please explain this? I am fascinated!

TeenAndTween Thu 27-Mar-14 10:11:34

I agree with Khara

fizzly Do you know about number lines?

Draw a number line with 10950 at the end. Then do repeated subtraction down from it. You can take 10x146 away 7 times (according to Khara, I haven't checked), and then end up with 730. Then take 146 away 5 times and end up with 0.

So you have taken away 75 lots of 146, so 75*146=10950.

Khara has gone 2 steps cleverer than this:

First, understanding you can take away 50*146 and 20*146 and 5*146 instead of just lots of 10 or 1.
Second, throwing away the number line and just using subtraction.

The next step on would be long division, which probably a 10 year old wouldn't be doing with these kinds of number.

(As an aside, you could have divide both by 2 to start with to simplify down to 5475*73 which would have been a bit easier)