Help me guys l don't know this ?

PEMDAS is the order of operations. Here’s how to solve this expression:

Expression: 15+14 ÷ 2-4•5

1.) Parentheses: there are no parentheses to
simply.
2.) Exponents: there are no exponents to
simply.
3.) Multiplication and Division: multiplication and division have an equal relationship meaning one operation doesn’t have a priority over the other. So, we work left to right as to what operation comes first.

In the expression 15+14 ÷ 2-4•5, we see that 14 ÷ 2 comes first because it’s to the left.

14 ÷ 2 = 7

15+(7)-4•5 after division, now we need to multiply.

-4•5 = -20

Therefore, 15+(7)-(20) is the simplification.

4.) Addition and Subtraction: addition and subtraction come after multiplication and division and also have an equal relationship. So again, we work left to right as to which operation comes first.

In the expression 15+7-20, 15+7 comes before 7-20.

15+7 = 22

So, (22)-20 after addition. Now we need to subtract.

22-20 = 2. That’s your answer!