It's easy to multiply fractions by mixed fractions or whole numbers. Start by turning your mixed fractions or whole numbers into improper fractions. Then multiply the numerators of both improper fractions. Multiply the denominators and simplify your result.
Dividing two fractions is the same as multiplying the first fraction by the reciprocal of the second fraction. The first step to dividing fractions is to find the reciprocal (reverse the numerator and denominator) of the second fraction. Next, multiply the two numerators. Then, multiply the two denominators.
In practice, the method of cross-multiplying means that we multiply the numerator of each (or one) side by the denominator of the other side, effectively crossing the terms over: The mathematical justification for the method is from the following longer mathematical procedure.
When you're starting out with teaching children fractions, objects or pictures of objects are a great way to understand how they work. Start with concrete items, like food or counters – you can use pasta pieces or dried beans in place of counters – then draw them as pictures.
One way to find the least common multiple of two numbers is to first list the prime factors of each number. Then multiply each factor the greatest number of times it occurs in either number. If the same factor occurs more than once in both numbers, you multiply the factor the greatest number of times it occurs.