Question

First estimate the answer. Then subtract to find the exact answer. 12 2/9 - 7 7/15 =
but i have to round each first

Answer 1

@jim_thompson5910

Answer 2

what does 12 2/9 round to?

Answer 3

11right

Answer 4

close, but no

Answer 5

10

Answer 6

now you're getting further away

Answer 7

its 12 sorry

Answer 8

7 7/15 rounds to what?

Answer 9

stays the same

Answer 10

so it rounds to 7?

Answer 11

yes

Answer 12

good

Answer 13

so

12 2/9 - 7 7/15

turns into

12 - 7 = 5

Answer 14

ok

Answer 15

that's the estimated answer

Answer 16

any ideas on how to get the exact answer?

Answer 17

yeah it askes for that too and no i dont know how to do this math

Answer 18

did you see how I did the last problem?

Answer 19

yes but i get confused im not good with with multiplication

Answer 20

do you know how to find the LCD?

Answer 21

yes common factors right
of 9 and 15

Answer 22

ok what is the GCF of 9 and 15?

Answer 23

45

Answer 24

that's the LCM, but that's what we wanted anyway

Answer 25

so we need to get each denominator equal to the LCM

Answer 26

ok

Answer 27

So we do this


\[\large 12 \frac{2}{9} - 7 \frac{7}{15}\]


\[\large 12 \frac{2*5}{9*5} - 7 \frac{7*3}{15*3}\]


\[\large 12 \frac{10}{45} - 7 \frac{21}{45}\]

Answer 28

what's next?

Answer 29

we subtract it right

Answer 30

not yet

Answer 31

we need to convert over to improper fractions

Answer 32

ok

Answer 33

so what do you get when you do so?

Answer 34

dont we multiply the whole number with the denominator and then add the numerator

Answer 35

good, you are correct

Answer 36

so do that for each mixed number

Answer 37

550/45- 336/45 right?

Answer 38

very good

Answer 39

now subtract

Answer 40

this is now possible because we have 2 fractions (with no whole parts) and the denominators are the same

Answer 41

214/45 right?

Answer 42

now convert that back to a mixed number

Answer 43

ok i dont know how to do that dont i divide 45 by 214

Answer 44

since 214/45 = 4.75555555555556 (use a calculator)

this means the quotient is 4

take the decimal part 0.75555555555556 and multiply it by 45 to get 0.75555555555556*45 = 34.0000000000002 which is practically 34

so the remainder is 34

-------------------------------------------------------

214/45 = 4 remainder 34

so...

\[\large \frac{214}{45} = 4\frac{34}{45}\]

Answer 45

and that means

\[\large 12 \frac{2}{9} - 7 \frac{7}{15} = 4\frac{34}{45}\]

Answer 46

oh okay thank you can you help me with two morte

Answer 47

yeah sure, but I have to do something real quick, so I'll brb