Multiply by the number of fractions - is, in fact, simple arithmetic.
Try to understand how to properly perform this action.
First of all, I must say that fractions are different: consider the common and decimal.
Decimal can be reduced to the ordinary leaston the basis of the name, for example, 0.325 - "zero point twenty-five thousandths of three hundred and" - immediately clear, how to write: 325 divided by 1000. Further it is possible to reduce it to 5, and then another 5 (or immediately notice the common factor of 25) .
In order to more accurately understand the structure of the process, for example, that virtually any number can be represented as a fraction with a denominator equal to unity: 325/1 is simply the number 325.
The very multiplication of fractions by the number produced by multiplying the numerator (the number on the slash), actually on the number that is given to you to perform this operation.
After multiplication may be that the numerator andthe denominator (the number under the slash) can be simplified by reducing the common factor: 7/35 = (7 * 1) / (7 * 5) = 1/5 (= 0.2), but you can not hurry up and take notice of this fact before multiplication, thereby simplifying his task, especially if we are talking about large numbers.
This on the condition of the fraction factor itself may be shot, in this case, the multiplication is performed according to the numerator the numerator by the denominator and the denominator is also possible to make simplification.
If the multiplier has a whole part of the additiondecimal (2.5), then forget about it, too, can not, and in this case it is possible to translate this number into improper fractions, multiplying the integer part in the denominator and adding it to the numerator (2.5 = 2 whole 5/10 = 1/2 = 2 whole ( 2 * 2 + 1) = 5/2) and then have to perform multiplication by a fraction of the condition.
If you are new to this business, the best advice -practice. Here even the collections of tasks are not needed. Just invent yourself any fractions and act, practice! If you select the physical and mathematical direction in the future, they are multiplying fractions will meet you or even in the integrals in physics)