how do i divide and multiply with decimals?

Question

please show me a simple example and then one with a really complicated sum.

Answer 1

multiplying with decimals

0.6 x 0.2 = 0.12

Dividing with decimals

0.6 / 0.2 = 3

- - - - - - - - - - -s-

Answer 2

Lets start with multiplication which is very easy. lets take 45.623 X 122.35 .i will show you how without doing the multiplying because iot is so easy. Simply put one number over the other 45.623
X122.35 now multiply forgetting about the decimal points and get an answer. Now simply count the number of decimal places in each of the two numbers, add those together and put that many decimal places in the answer. No need for worry, your answer will be correct.

In dividing lets say 23. 1 / .12 , set it up as a long division problem like this
________ *
.12 I 23.1

now move the decimal in the outside number to the right until it becomes a whole number that is 2 places. And do the same with the number inside the division sign that is also 2 places (adding a 0 as a place holder. What you have actually done is multiply each of the numbers by 100 and this does not change the answer. Now just divide the way you always have and put a decimal in the answer directly above the one in the inner number. Your answer will be correct if you divide correctly

* When it prints out the division sign is in the wrong place, I hope you can see where it should go. It should be over the second number only

Answer 3

Pretty much the same you do with whole numbers, the only difference is that you have to keep track of the decimal point. In general, if you multiply a number with n digits after the decimal points with a number having m digits after the decimal point, you can (temporarily) ignore the decimal points, multiply them as you would whole numbers, and then place a decimal point in the result such that n+m digits are to the right of it. As an example 1.2 × 1.2 = 1.44, since 12×12=144, and there is one digit to the right of the decimal point in the first factor, one digit to the right of the decimal point in the second, so there are two digits to the right of the point in the result.

A more complicated example:

...... 3.141
.... × 6.66
--------------
.....18846
...188460
.1884600
--------------
20.91906

In this case, there were three digits after the point in the first number, and two after the point in the second, so there were 5 digits after the point in the result.

For division, if the dividend has a decimal point, then one need only place a decimal point in the quotient directly above it, and otherwise carry out the division normally. For instance:

...1.53
6|9.18
...6
---------
...31
...30
----------
......18
......18
----------
....... 0

If the divisor has a decimal point, one may compensate for it by shifting the decimal point to the right the same number of places in _both_ the dividend and the divisor. This corresponds to multiplying both numbers by the same power of 10, and for all numbers a and b (b≠0) (a×10^n)/(b×10^n) = a/b × (10^n)/(10^n) = a/b × 1 = a/b. So for instance: 12 ÷ 2.4 = 120 ÷ 24 = 5. Or for a more complicated example:

10.92 ÷ 3.9 = 109.2 ÷39 = 2.8

......... 2.8
39|109.2
.......78
-------------
........312
........312
-------------
............0

Answer 4

Found this for you:http://www.mathsisfun.com/dividing-decimals.html

Answer 5

With a calculator? :(