## Pre-Algebra Tutorial

#### Intro

Teacher Proficiency/Basic Math Skills

These exercises revisit math foundations.Brushing up on these concepts improves pre-algebra work.

#### Sample Problem

1. How do you divide fractions?

2. How do you add and subtract unlike fractions?

3.How do you turn fractions into decimals;and decimals into fractions?

#### Solution

1.Multiply one fraction straight across the other.First, you must flip the second fraction over.

```   1/2 (/) 1/4 = 1/2 * 4/1   1/2 * 4/1 = 4/2
which when simplified= 2   Answer: 1/2 (/) 1/4= 2
```

2.Turn the unlike fractions into like fractions (same bottom number), using cross multiplication, which is multiplying the diagonal top and bottom numbers.
First you have to find out how many 8ths = 3/4

You write 3/4 = x/8. Then create an algebra equation to find out how many.

```3/4 - 1/8      3/4 = x/8   cross multiply 4*x and 8*3
So then 4x=24    get the X variable alone
```

```4x/4 = 24/4.  x=6    So  3/4 = 6/8 and;
6/8 - 1/8 = 5/8 answer:  3/4 - 1/8 = 5/8
```

This may seem like the long way, but it is the algebra way. Getting good at cross multiplication and solving for x will get you through geometry, algebra 1&2.

3.To turn fractions into decimals, use long division. Divide the top number which is usually smaller,by the bottom number. First put the decimal indent, then divided.
1/4= .25

To turn decimals into fractions, put the decimal over 100. .25/100; next, remove the decimal point.
It becomes 25/100; Then simplify this fraction to 1/4

Next Tutorial, we’re going to drill more on changing decimals to fractions, to percent. 