(14)²

The Lovely Muffin

Can anyone help me work out that sum please? As in, explain to me how to work it out?

(14)²

Thanks.

LeixlipRed

The way you say it is "14 squared". Which means 14 multiplied by itself or 14 x 14. See here to see how to work with questions like this in general.

The Lovely Muffin

LeixlipRed wrote: »

The way you say it is "14 squared". Which means 14 multiplied by itself or 14 x 14. See here to see how to work with questions like this in general.

Thank you so much, that site you linked to is very helpful.

LeixlipRed

No worries.

gondorff

Incidentally, neat way to square numbers mentally...

14... (10+4)(10+4)... 100+40+40+16
83... (80+3)(80+3)... 6400+240+240+9
etc.

Was taught this a long time ago and with practice it becomes effortless.

LeixlipRed

Yes, in general if you want to square something a bit tricky you can use the fact that [latex](a+b)^{2} = a^{2} + 2ab + b^{2}[/latex]

ray giraffe

LeixlipRed wrote: »

Yes, in general if you want to square something a bit tricky you can use the fact that [latex](a+b)^{2} = a^{2} + 2ab + b^{2}[/latex]

Don't forget that the most important thing is to understand what you're doing, not to get the right answer

http://www.youtube.com/watch?v=DfCJgC2zezw

I suppose the new "New Math" is Project Maths? :pac:

eoins23456

can you extend it to numbers from 100-999 like this.
(307)^2
(300+7)(300+7)=90000+2100+2100+49=94249 which is true
101^2

(100+1)(100+1)=10000+100+100+1=10201

Just was trying random ones in my head

LeixlipRed

Yeh, if you look at my last post you can break any number x up into two parts that sum together i.e. a+b = x and then you can square them like I showed. It follows from this diagram here:

link

MathsManiac

ray giraffe wrote: »

Don't forget that the most important thing is to understand what you're doing, not to get the right answer

http://www.youtube.com/watch?v=DfCJgC2zezw

...in which case, of course, (14)² = 220, obviously.

(P.S. Purple Bobbin, please ignore this post!)

Mellor

MathsManiac wrote: »

...in which case, of course, (14)² = 220, obviously.

(P.S. Purple Bobbin, please ignore this post!)

You mean 304



Anyway
I was always able to do squares in my head up to 22 without haveing to break them down. Somewere obvious memorised, like 15 and down.

I had a handy trick for any that end in 5, but can't figure out how to explain it here.

you drop the 5, time by the number one greater and stick 25 on the end,

65*65=6*6[25]=42[25]

MathsManiac

Mellor wrote: »

You mean 304

Nope.

And I give up. Where'd ya get the 304? (Edit: never mind; I can see it now, but I think changing base halfway through is kinda cheating!)