If the number is x, 5x+2=2x-4, so putting x's on the left and numbers on the right we get 3x=-6, so x is -2. The equals sign changes positive to negative and negative to positive when transfers are made across it. Put x=-2 and check out the question: 5 times the number is -10 plus 2 is -8, and twice the number is -4 less 4 is also -8. Treat negatives as direction backwards and positives as direction forward: negative is steps back and positive is steps forward, so the number -2 is two steps back. Multiply by 5 means 10 steps back; plus 2 is 2 steps forward, making 8 steps back. Twice 2 steps back is 4 steps back; less 4 is 4 steps further back making 8 steps back.