How can you tell before you divide 425 by 9 that the first digit of the quotient is in the tens place?

Question

jim_thompson5910 · Answer

Well assume that the first digit in the quotient is in the hundreds place

so say the quotient is 100 (the smallest 3 digit number) which would mean 100*9 = 900

jim_thompson5910 · Answer

that's too big, which means that the quotient has to be smaller than 100

campbell_st · Answer

well if you look at the

4... 9 doesn't divide into 4... so that means the answer can't be in the 100s

so now look at 

42   9 divides into 42  6 remainder 6... so the answer will be in the 60s... 

hope this helps

anonymous · Answer

Umm could you please dumb that down a bit?

jim_thompson5910 · Answer

let's say we wanted to divide 360 by 9

360/9 = 40

40 is the quotient

we could multiply both sides by 9 to get

360 = 9*40

notice how 360 equals 9 times the quotient of 40

jim_thompson5910 · Answer

now let's say we go back to the original problem of 425/9

if x is the quotient, then

425/9 = x

multiply both sides by 9 to get

425 = 9x

jim_thompson5910 · Answer

Now if x is some 3 digit number, then let's assume that it's the smallest 3 digit number possible

jim_thompson5910 · Answer

so let's assume that x = 100

if that were true, then

425 = 9x

425 = 9*100

425 = 900

but the right side is too big, so that means that x is too big

which tells us that x is at most a 2 digit number

anonymous · Answer

Oh okay. thanks so much!

jim_thompson5910 · Answer

yw