First, you know that the result is going to be negative, because one number is greater than zero and the other is less than zero. So we can ignore the signs and just deal with the numbers. A decimal can always be converted to a fraction, so to do this look at the decimal part. For example, 2.6 would be 2 and 6 tenths, which cancels down to 2⅗. Expressed as an improper fraction this would be 13/5 because the whole number 2 contains 5+5=10 fifths, then we add 3 more fifths to get 13. Another way to express a decimal as a fraction is to write down the number without any decimal point then count the decimal places. Suppose there are 3 decimal places then we write 1 followed by 3 zeroes to make 1000 and we divide by this number. For example 4.375 is the same as the fraction 4375/1000. This fraction can be reduced by dividing top and bottom by 125 to give us 35/8 (you don't need to divide by 125 straight out, you can keep dividing by 5 until you get 35/8).
Now that you've turned the decimal into a fraction you can multiply two fractions. There may be some cancelling to reduce the final answer. Remember to insert the negative sign in front of the answer because you started with one number positive and the other negative.
EXAMPLE
6.75 × (-2/3). Remember the negative sign for later.
6.75=675/100=27/4.
27/4 × 2/3=9/4×2=9/2. So the answer is -9/2. This is an improper fraction which is the same as the mixed number -4½.
