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g'day welcome to tech math Channel what

we're gonna be having a look at in this

video is a way of working the square

root out of numbers these are going to

be looking where we've got the square

perfect squares that are occurring less

than 100 but we haven't with these out

in just seconds

okay so I'll show you how to do this

anyway so first off we'll give you an

example so how fast can you work at the

square root of 576 I'll give you a

couple of seconds okay times up

yeah did you get the answer of positive

or minus 24 if you did that's that's

that's great you got the right answer

there if not I'm gonna show you how to

through these you know just by the way

before I get any further the square root

iya it's really important that you

actually identify this as a positive or

negative answer because say negative 24

times negative 24 gives us the answer

526 the same way 24 times 24 gives us Y

an answer of 576 so just before I go on

just just make a note of that

having said that I'm probably not gonna

worry about doing the positive and minus

for the the rest of these numbers here

I'm just gonna put them down as numbers

and you can assume that there's a

positive or minus there so I'm gonna

show you how we do this and it's going

to involve knowing your squares all the

way up to I've done it up to nine

because I think you should probably know

it N squared I think you should know

these already anyway I think probably

most of you will but you're gonna see

that I've got to shot it down here the

squares 1 squared is 1 2 squared is 4 3

squared is 9 4 squared is 16 and so on

and so forth we're gonna be using these

a fair bit you're also going to notice

first off that I've actually uh put the

units of these in a different color I'm

just gonna draw your attention to those

actually right now we'll be first are

working out our answer here so why don't

we do it is as follows the way we work

at square root of 576 using this is as

follows okay so

first thing we do is we have a look at

this particular units answer the number

here the Kahless six and we're looking

for a square root here the corresponds

to this or a square sorry it's square

that corresponds to this so 16 does and

36 does the square root that goes

alongside of those we have 4 when we're

talking about our 16 and we have 6 when

we're talking about 36 so we're answer

is going to finish you know 4 or 6 and

we're gonna work out for sure which one

this is in a little second but first off

we have to work out now ere are our

first digit so I'm gonna cross out

there's two digits that's next thing you

do and we just still directly now with

this five okay yeah we're gonna have a

look here along here in ear square

answers here we're looking for a number

that flickers just below five so it's

only gonna be the number five itself or

the one closest to five which is under

okay so gonna go along here and you can

see one four fours just under five and

nines too much so we're gonna be dealing

with this for now the square root of

four is two twos the first part of our

answer

okay now we're always there now we have

to just working out whether or not we're

dealing with is it 24 or 26 is our

answer and the way we do this as follows

is we get out to here and we just

multiply by the next number up okay and

I mean the next number up from 2 which

is 3 so 2 times 3 equals 6 now we have a

look at this 6 and pretty much what we

do is as follows it is 5 here is less

than this 6 we choose the lesser number

okay

if it was more we choose the bigger

number okay so 2 times 3 is 6 5 is less

than 6 so we choose the lesser number

here so we're answer it's 24

okay that's a bit of going through I'll

tell you what we'll go through a couple

more of these you'll pick them up as we

go along and then what I recommend is

you probably are be able to start

pausing it and giving it a go okay so

let's get into another one of these so

what about we do 1849 are we gonna work

out the square root of this so first off

once again what we do is we're looking

at this diet here okay they died and the

number that goes along without knowing

could either be a three or a seven

you notice these complimentary numbers

add up to 10 to it so it's kind of a

handy little thing the next thing I do

is I cross out these two numbers

okay so answers gonna finish it a three

or a seven now I look at this 18 so 18

and I go down here and I'm looking and

16 just occurs below 18 25 too much so

the square root of 16 is 4 the first

part of our answer is 4 okay 4 times 5

okay

4 times 5 is 20 and now I compare this

to 18 here so 18 as you'll see is less

than 20 so we choose once again the

lesser number okay so we're answer is 43

you get faster and faster and faster of

these okay keep practicing them you will

get used to doing them okay okay what

about one more of these are 3364 okay

pause it give it a go okay so looking at

the last number here it could be either

or two or an eight okay so let's cross

out these two digits here and now what

we do is we are looking for that first

digit okay so it's going to be a five

okay you're probably working that out

really really quickly okay because five

five is twenty five six six is thirty

six that's too much isn't it so let's go

five times six five times six is thirty

33 is bigger then 30 so we're gonna

choose the bigger number we have an

eight

so our answer

is 58 okay what about another one what

about we have a different one here we'll

do

2025 now this is a nice and easy one

you'll see why okay pause it and give it

a go

okay so 2025 you're gonna see that can

only be a 5 at the end here because

there's no other option

okay cross it out and then we're looking

for the number which is going to be

occurring under here okay so 4 squared

is gonna be 16 5 squids too much so it's

going to be a 4 but this Cerreta because

we don't need to differentiate between

whether it's a five or it's at five

isn't it so 45 times 45 that's our

answer

pretty cool right okay couple more of

these just about three more of these

I'll put them out there I recommend them

and see here you go

so five thousand one hundred and eighty

four okay so our last number could

either be a 2 or an 8 okay 7 squared is

49 so this is gonna be a 7 okay

7 times 8 is 56 and 56 is 50 ones less

than 56 so we're going to choose the two

okay

this is how I start doing these in my

head I'm gonna start doing the more and

more like this going to do the rest of

my that I reckon so

what about 1444 okay so the last number

here could be a 2 or it could be an 8

okay so 14 16 squares are for squares

too much three squares good so it's

going to be three three fours are twelve

fourteen greater than 12 so we're gonna

choose the greater number which is an 8

38

all right lucky last one out of all them

is 8281 okay so as you see here 81 well

81 we could I'm on the a look at the

last time here no it's sort of tempting

to go hating one that hey wait a second

that's dying I'm really gonna look at

the last digit here so 81 it could be a

one or a Naaman okay so what we'll do

now is we'll cross that out and 82

okay so 82 yeah once again this is gonna

be annoying okay it's not enough because

that's not necessarily annoying so we've

got nine okay so 9 times 10 is 90 82 is

less than 90 so I'm gonna choose a

lesser value we're gonna 91 anyway what

did you think of that particular trick

there it's that's not a bad trick okay

it does take a bit of getting used to

but once you get used to what it's

actually fairly handy I kind it's a

great little way of working about you

starts me out of work the mount as you

see towards the end much much much much

much faster okay

and yeah you will make the odd mistake

but they everybody does this and now in

a future a couple of videos I am gonna

be looking at about how to work out the

are how to calculate squares of any

number okay the laborious slow out doing

this but it's not the slowest way ever

just a nice little trick for doing these

and something you may or may not know

how to do already you know thanks for

watching see you next time bye