How do you simplify (6\times 7) + ( 4\times 5) - 12?

Mar 4, 2018

By using PEMDAS, you'll get

Explanation:

Since this problem is an Order of Operation, I will be using PEMDAS:

P - Parentheses
E - Exponents
M - Multiplication
D - Division
S - Subtraction

Note: For multiplication and division, do whichever one that comes first in the equation and same for addition and subtraction. :)
Now, let's start working it out!

Let's solve inside the Parentheses first:

$\left(6 \times 7\right) + \left(4 \times 5\right) - 12$

$\left(42\right) + \left(20\right) - 12$

Note: You don't have to keep the parentheses now...

$42 + 20 - 12$

We will skip Multiplication and Division because there is none.
That will then leave us with Addition and Subtraction. Addition comes first in the problem, so we'll find the sum, now!

$42 + 20 = 62$

$62 - 12$

Now we have to do Subtraction!

$62 - 12 = 50$

$50$ is now your answer. I hope you understand my explanation! If not, look at this Khan Academy's example on order of operations. My knowledge is my source for this answer.

Mar 4, 2018

$= 50$

Explanation:

Count the number of terms first. They are separated by the $+ \mathmr{and} -$ signs.

There are $3$ terms.

Notice that the parentheses are not necessary at all .. Multiplication is a stronger operation than addition or subtraction, so would be done first anyway. I will leave them out to emphasise this concept

$\textcolor{b l u e}{6 \times 7} \text{ "color(red)(+4xx5)" } \textcolor{g r e e n}{- 12}$

$= \textcolor{b l u e}{42} \text{ "color(red)(+20)" } \textcolor{g r e e n}{- 12}$

$= 62 \textcolor{g r e e n}{- 12}$

$= 50$

Note that you can add or subtract in any order as long as the signs stay with the correct number.

$= \textcolor{b l u e}{42} \text{ "color(green)(-12)" } \textcolor{red}{+ 20}$

$= 30 \text{ } \textcolor{red}{+ 20}$

$= 50$

Or you could do:

$= \textcolor{b l u e}{42} \text{ "color(red)(+20)" } \textcolor{g r e e n}{- 12}$

$= \textcolor{b l u e}{42} \text{ } + 8$

$= 50$