The temperature in Hillsville was 20° Celsius. What is the equivalent of this temperature in degrees Fahrenheit?

This problem translates to the expression 3 {[2 - (-7 + 6)] + 4}. While dealing along with multiple grouping symbols, begin from the innermost set and work your way out. Add and subtract in order from left to right inside the brackets. Notice that subtraction is the same as adding the opposite so 2 - (-1) becomes 2 + (+1) = 3; 3 {[2 - (-1)] + 4]}; 3 [3 + 4]. Multiply 3 × 7 to ?nish the problem; 3 [7] = 21.