As you will understand, R7 asks complete Calculations from you, on paper.
Just answers are not enough. It's about the steps you have to take - in the right order!
For example:
4 + 6 x 3 -4 = 4 + 18 - 4 = 22 - 4 = 18 and NOT:
4 + 6 x 3 - 4 = 4 + 18 = 22 = 22 -4 = 18, because 22 is not equal to 18...