Answer:
Option b - Subtract
Step-by-step explanation:
Given : Expression 
To find : Which operation should be completed first in the expression below?
Solution :
P - Parentheses
E - Exponent
D - Divide
M - Multiplication
A - Addition
S - Subtraction
In the first step we solve the bracket in the expression 
So, we do subtraction i.e. 12-8=4
Therefore, option b is correct.
Answer:
40
Step-by-step explanation:
the range is the number between the highest and lowest number. the lowest in this is 5 and the highest is 45
45-5=40
Answer:
it is 1/4
Step-by-step explanation:
20/60=10/30=1/3
Answer:
They are: area of sector and area of triangle
Step-by-step explanation:
Area of segment=area of sector - area of triangle
So we need both the area of sector and area of triangle to calculate for the area of a segment
Lets say your numbers are these...
10,20,30,40,50,60,70,80,90 and 100
you would add those to get 650
Now how many numbers did you add?
You added 10
so now divided
650 by 10
you get 65
that is the mean of those numbers!