Pre algebra problems are termed as the basic rules of mathematics that are very essential for the understanding, the concept of algebra at a higher level.

Pre algebra problems include fractions, percentages, the number theory, decimals, types of numbers, exponents, the PEMDAS rule, the greatest common factors etc. The **fractions **are defined as some part of the whole. Like $\frac{2}{3}$, $\frac{7}{5}$, $\frac{9}{2}$ are the examples of fractions. **Percentages**, which are defined as the part out of the total of 100, as a denominator.

The

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1.

$a + b = b + a$ and $a \times b = b \times a$.

2.

$(a + b) + c = a + (b + c)$ and $(a \times b) \times c = a \times (b \times c)$

For example $(2 + 3) + 5 = 2 + (3 + 5) and (5 \times 3) \times 10 = 5 \times (3 \times 10)$.

3. The Distributive Law

$a \times (b + c) = a \times b + a \times c$ and $a + (b \times c) = (a + b) \times (a + c)$.

1. Simplify 2x + 5 (3x + 4x)

To simplify this, we apply the PEMDAS rule

Simplify the brackets first, we get 2x + 5(7x).

Multiply 5 by 7x, we get

2x + 35x

Now add both the terms.

This can be simplified to 37x

2. Solve for x.

3x + 22 = 12 x + 4

We subtract 4 from both sides, we get

3x + 22 - 4 = 12x + 4 - 4

3x + 18 = 12x

Subtract 3x from both sides, we get

3x + 18 - 3x = 12x - 3x

18 = 9x

Now we can divide both sides by 9, which gives x = 2

3. What is 15 % of 640?

To solve this, we multiply $\frac{15}{100}$$ \times 640$, we get 96.

Hence we can say that 15 % of 640 is 96.