Fractions

Question 1

What mathematical operation does a fraction represent?

• add
• subtract
• multiply
• divide

Answer 1

Divide.

Question 2

What is a numerator?

Answer 2

The top number of a fraction.

Question 3

What is a denominator?

Answer 3

The bottom number in a fraction.

Question 4

How do you add fractions?

Answer 4

You first have to get a common denominator. Then just add the numerators.

Question 5

How do you subtract fractions?

Answer 5

First, you have to get common denominators. Then you have to subtract the numerators.

BE CAREFUL! Make sure you distribute the negative to each term of the second numerator.

Question 6

What is a least common multiple?

Answer 6

It is the smallest number that can be divided by both of the starting numbers.

For example, the least common multiple of 8 and 12 is 24.

Question 7

How do you find the least common multiple?

Answer 7

1. Multiply the biggest number by 2.
2. Ask yourself whether the other number goes into the answer. If yes, that’s it. If not, keep going.
3. Multiply the biggest number by 3.
4. Ask yourself whether the other number goes into the answer. If yes, that’s it. If not, keep going.
5. Repeat these steps until you find the LCM.

Question 8

What is the least common multiple of 7 and 13?

Answer 8

Question 9

How do you multiply fractions?

Answer 9

You multiply the numerators together and you multiply the denominators together. Then you need to make sure to reduce the fraction by taking out the greatest common factor.

Question 10

What’s the trick to more easily multiply fractions with bigger numbers?

Answer 10

Try to cross cancel, first. So if anything on the top can be simplified with anything on the bottom, cross them out, first.

Question 11

How do you divide fractions?

Answer 11

You multiply the reciprocal. This means you should do the following.

1. Flip over the second fraction.
2. Multiply the numerators together and multiply the denominators together.

Question 12

When is a fraction undefined?

Answer 12

When the denominator is zero, since it’s impossible to divide by zero.

Question 13

When is a fraction equal to zero?

Answer 13

When the numerator is equal to zero, since anything divided by zero equals zero.

Question 14

How do you convert a fraction into a decimal?

Answer 14

You do long division.

Question 15

How do you convert a decimal into a fraction?

Answer 15

The numerator is just the same number, but written without the decimal.

The denominator is 1 with as many zeros as there are decimal digits.

You should try to reduce the fraction once you convert it.

Question 16

How do you calculate the “fraction of” something?

Answer 16

“Of” in math means multiply, so you multiply the fraction by the quantity.

Question 17

What is a greatest common factor?

Answer 17

It’s the biggest number that multiplies into each of the starting numbers.

For example, the greatest common factor of 36 and 54 is 18.

Question 18

How do you find the greatest common factor?

Answer 18

1. Write a list of all of the factors for each number.
2. Rewrite those lists in ascending order.
3. Find the biggest number that is in both lists.

Question 19

What is the greatest common factor of 16 and 24?

Answer 19

Question 20

What is prime factorisation?

Answer 20

It’s finding all of the prime numbers that multiply together to find the number you’re given.

Question 21

What is the prime factorization of 100?

Answer 21