How's your mental arithmetic?

tenofspades · 14/10/13 - 21:39

On another thread someone was asking £6.31x 18.
Are you someone that routinely works stuff like that in your head, or are you someone that turns to the paper+pen, or calculator?

Iphigenia · 14/10/13 - 21:42

I Could do it in my head but probably would use pen and paper. I don't generally do over 12 times anything in my head. I was a pre-decimal child.

Picto · 14/10/13 - 21:44

My mental arithmetic skills are declining but i'm not sure why. It just doesn't add up

Raquelos. · 14/10/13 - 21:44

I'm not particularly consistent in my approach. That particular sum I did in my head, but catch me in a lazier mood and I would just as easily have gone for a calculator.

[Deleted User] · 14/10/13 - 21:45

tenofspades wrote: »

On another thread someone was asking £6.31x 18.
Are you someone that routinely works stuff like that in your head, or are you someone that turns to the paper+pen, or calculator?

Always check on a calculator after I try. I don't really trust my head with numbers.

- A_Zombie

Muze · 14/10/13 - 21:48

You know what's slightly alarming.

Even though I always loved maths in school, we did no mental arithmetic at all, in fact I'm not sure we were ever taught to multiple decimals without a calculator.

Weird.

thewaywardbus · 14/10/13 - 21:50

What do you get if you multiply 1 nutter by 1 lunatic.

Is that the sort of mental arithmatic you mean?

[Deleted User] · 14/10/13 - 21:52

tenofspades wrote: »

On another thread someone was asking £6.31x 18.
Are you someone that routinely works stuff like that in your head, or are you someone that turns to the paper+pen, or calculator?

I thought the OP was asking how much he'd take home rather than 6.31*18.

netcurtains · 14/10/13 - 21:54

It took me ages the other day to work out that two lots of forty five minutes was an hour an a half.

[Deleted User] · 14/10/13 - 21:55

Always in my head unless it's tricky and accuracy is crucial, in which case I do it in my head then check on calculator.

I was one of those strange children who begged my folks to write me pages of sums out so I could do them for fun, and would get them to ask me sums while they sat with a calculator.

TrollHunter · 14/10/13 - 21:56

karijn wrote: »

I thought the OP was asking how much he'd take home rather than 6.31*18.

Seeing as he didn't have the decency to actually explain what he wanted to know, instead preferring to dish out schoolchild style abuse, we'll never know.

But as for mental arithmetic, I'll use the old noggin', unless I'm sat on my laptop in which case I'll press the Windows key, type "calc", press ENTER then up pops the handy calculator tool and off I go.

netcurtains · 14/10/13 - 21:58

rancidbeings wrote: »

Always in my head unless it's tricky and accuracy is crucial, in which case I do it in my head then check on calculator.

I was one of those strange children who begged my folks to write me pages of sums out so I could do them for fun, and would get them to ask me sums while they sat with a calculator.

My son is one of those weirdo's. He loves me writing out a pages of sums for him. "Did I get them all right mum?" Buggered if I know!

[Deleted User] · 14/10/13 - 22:00

netcurtains wrote: »

My son is one of those weirdo's. He loves me writing out a pages of sums for him. "Did I get them all right mum?" Buggered if I know!

Give him the calculator and tell him to check for himself!

acker · 14/10/13 - 22:00

Learnt it all at Ladbrokes in fractions ...relearnt it all at betfair in decimals

[Deleted User] · 14/10/13 - 22:01

netcurtains wrote: »

It took me ages the other day to work out that two lots of forty five minutes was an hour an a half.

It always takes me forever to work out the cooking time for the Christmas turkey.

Arcana · 14/10/13 - 22:03

Less reliable than my physical arithmetic but always available wherever I go.

Toby LaRhone · 14/10/13 - 22:07

tenofspades wrote: »

On another thread someone was asking £6.31x 18.
Are you someone that routinely works stuff like that in your head, or are you someone that turns to the paper+pen, or calculator?

You break it down.
My dad taught me 50+ years ago.

£108 (6 x 18)
+
£5.40 (30p x 18)
+
18p (1 x 18)
=
£113.58

On payday his pals gave him their payslips to check if their tax was correct.

Toby LaRhone · 14/10/13 - 22:07

karijn wrote: »

It always takes me forever to work out the cooking time for the Christmas turkey.

It's at least a month for sprouts :eek:

chrisjr · 14/10/13 - 22:08

Muze wrote: »

You know what's slightly alarming.

Even though I always loved maths in school, we did no mental arithmetic at all, in fact I'm not sure we were ever taught to multiple decimals without a calculator.

Weird.

Some of us went to school before calculators were invented!:eek::D

So multiplication and division was done the old fashioned way with pen and paper...

netcurtains · 14/10/13 - 22:09

karijn wrote: »

It always takes me forever to work out the cooking time for the Christmas turkey.

Oh I know, 45 mins per Kg or something and it weighs some random amount like 2.86Kg. I have no chance anyway as I'm still working in pounds and ounces. These days I use my mums golden rule of cooking, when it's brown it's done and when it's black it's buggered.

Belligerence · 14/10/13 - 22:11

Used to be great at mental maths. Could even square numbers 1-49 off the top of me head, but I forgot the formula needed to do so.

Toby LaRhone · 14/10/13 - 22:15

Delia suggests you stab it to see of it bleeds.
If it squawks gag it and put it back in.

wear thefoxhat · 14/10/13 - 22:17

My mental maths is embarrassingly bad, though bizzarely I gave birth to one of scotland's finest mathematicians

NX-74205 · 14/10/13 - 22:17

Good, but then I couldn't do my job if it wasn't.

[Deleted User] · 14/10/13 - 22:21

I went to school before calculators, so we did everything with pen and paper. Every Friday afternoon at primary school we did at last an hour of mental arithmetic. No pens or paper allowed, all calculations to be done in your head. And this was pre decimal currency, so you'd get sums like : "You have 39/11d in your piggy bank and you want to buy one comic at 6d, a box of chocolates at 2/6d and a bunch of flowers for 3/11d. How much change to you have?" And we'd have to work it out in our heads!

Andrue · 14/10/13 - 22:26

tenofspades wrote: »

On another thread someone was asking £6.31x 18.
Are you someone that routinely works stuff like that in your head, or are you someone that turns to the paper+pen, or calculator?

I might initially approximate it as £7*18 but for accuracy would reach for a calculator.

Edit: Actually 6*18 would be better, but meh

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