2,3,4,5,6 fill in +, - sign equals 18 how to do

2,3,4,5,6 fill in +, - sign equals 18 how to do

Is there a one missing?
53-42+1+6=18

How many meters and decimeters is 2.5 micron

2.5 micron is equal to - 6 meter of 2.5 × 10 and - 5 decimeter of 2.5 × 10

Calculate (1 + 1 / 2) (2 times of 1 + 1 / 2) (4 times of 1 + 1 / 2) (8 times of 1 + 1 / 2) (16 times of 1 + 1 / 2)

(1 + 1 / 2) (2 times of 1 + 1 / 2) (4 times of 1 + 1 / 2) (8 times of 1 + 1 / 2) (16 times of 1 + 1 / 2) = 2 (1-1 / 2) (1 + 1 / 2) (2 times of 1 + 1 / 2) (4 times of 1 + 1 / 2) (8 times of 1 + 1 / 2) (16 times of 1 + 1 / 2) = 2 (2 times of 1-1 / 2) (2 times of 1 + 1 / 2) (4 times of 1 + 1 / 2) (8 times of 1 + 1 / 2) (16 times of 1 + 1 / 2) =. = 2 (1 -