Evaluating an operation means that we need to replace the variables (if we have) by numbers, and solve the operations.
2) It can change the order in which we perform the operations, that is why it changes the final value.
3) The division.
4) Charles.
What is an expression?
An expression is any operation between variables that you can think of. An example is:
a + b
This is the sum between two numbers.
To evaluate the expression, you need to assign numbers to these variables, for example, if we use:
a = 2
b = 3
Then the expression becomes:
2 + 3
And now we can solve this operation:
2 + 3 = 5
So the value when a = 2 and b = 3, is 5.
2) The numerical expression here:
80÷8*5 + 4²
If you solve it as it is, you need to do the divisions and products first (from left to right), and then the sum, so we have:
80÷8*5 + 4²
= 10*5 + 4²
= 50 + 4²
= 50 + 16
= 66
Now, if you group terms, then the operations in the groups should be done first, so for example, in:
80÷(8*5) + 4²
The first thing we need to solve is the product, then we get:
80÷(8*5) + 4²
80÷40 + 4²
2 + 4²
2 + 16
18
The value has changed.
3) First the sums because thes are inside parenthesis, then from left to right, first the multiplication, lastly the division.
4) Charles is correct:
2*3 - 2
First the product:
2*3 - 2
= 6 - 2
Then the difference:
6 - 2
= 4