First we simplify calculations that are in parentheses. Second, we calculate exponents and roots. Then, we simplify multiplication and division, which are solved on the same level of importance and from left to right. Finally, we calculate addition and subtraction, which are also on the same level of importance, from left to right. Let's now consider our expression.
[ 20 + ( 2.5 * 3 ) ] - 3^3
We first need to simplify the value of the expression in the parentheses. Within the parentheses, we need to calculate the product
[20+ (2.5* 3)] -3^3 multiply ⟶ [20+7.5] -3^3
Now we can calculate the sum in the brackets.
[20+7.5]-3^3 add ⟶ 27.5-3^3
Next, we need to calculate the exponent expression.
27.5-3^3 calculate power ⟶ 27.5-27
Finally, we can finish evaluating our expression by subtracting 27 from 27.5.
27.5-27 subtract ⟶ 0.5
