show me the work for 3.780 divided by 18

Question

3.780/18 please show work

Answer 1

The simplest way to do the division is to do two simple divisions, because 18 has factors 6 and 3 amongst others and I guess you can divide by these numbers fairly easily. So divide by 3 first so that the number you will eventually divide by 6 is smaller. 3.780/3=1.260. To work out where the decimal point goes in the answer, write the answer a digit at a time over the number you're dividing and you see the 2 lines up over the 7 next to the decimal point, so that's where the decimal point is in the answer. Now divide 1.260 by 6. Write 0 over the 1 because 6 won't go, then write the decimal point and then divide 6 into 12. The 2 goes immediately after the decimal point and finally 6 goes into 6 once: 0.210 is therefore the answer when you divide 3.780 by 18. Check with your calculator. You don't really need the end zero, but because it's an indication of how accurate the result is leave it in.

Answer 2

3.780/18:

Know the divisibility rules. (And know that while 0 is considered a significant digit in science, we can do away with it in math. Hence, 3.780=3.78)

1. Both numerator and denominator are even, which means they're both divisible by 2. Hence, 3.78/18=(1.89*2)/(9*2).

2. Cancel out common factors. So it becomes 1.89/9.

3. 1.89 is divisible by 9 because 1+8+9=18. Hence 1.89/9= (.21*9)/9

4. Again, cancel out common factors. Thus, (.21*9)/9= .21/1. Hence .21

Answer 3

Given: 3780/18=

Sol.A: 18=2x3x3=2x9, so if 3780 is divisible by 18, 3780 would be divisible
by both 2 and 9 as well, because 2 and 9 are co-prime, don't share any
divisors other than 1.*

3780/2=1890 and 1890/9=210.  That is: 3780/(2x9)=(3780/2)/9=1890/9=210 

The answer is: 3780/18=210

Sol.B: Think simple multiple of 18 nearer to 3780.
18x2=36, so 18x200=3600   Thus, 3600/18=200  

3780-3600=180, and 180/18=10   That is:

3780/18=(3600+180)/18=3600/18 + 180/18=200+10=210 

The answer is: 3780/18=210

* The ones digit of 3780 is 0, so 3780 is divisible by 2.   And the sum of each digit of 3780 is 18 (=3+7+8+0), so 3780 is divisible by 9