7) 24 * 7,21 : 1,68 * 0,002

First, multiply 24 by 7.21:
$$24 * 7.21 = 173.04$$
Next, divide 173.04 by 1.68:
$$173.04 : 1.68 = 103$$
Now, multiply 103 by 0.002:
$$103 * 0.002 = 0.206$$

Answer: 0.206