7.1. The numbers $1,2,3,4,5,6$ were written in some order and denoted by the letters $a, b, c, d, e, f$. Can the equality

$$
(a-1)(b-2)(c-3)(d-4)(e-5)(f-6)=75 ?
$$

#
# Answer. It can.

Solution. Arrange the numbers as follows:

$$
(6-1)(3-2)(4-3)(5-4)(2-5)(1-6)=75 .
$$

Comment. A correct answer without justification (without providing an example) - 0 points.