(1) When a, b and c are all positive numbers,
a/|a|+b/|b|+c/|c|+abc/|abc|
= 1+ 1+ 1+ 1
=4
② When the numbers A, B and C are all negative,
a/|a|+b/|b|+c/|c|+abc/|abc|
=- 1- 1- 1- 1
=-4
(3) When there are two positive numbers and one negative number in the three numbers A, B and C,
a/|a|+b/|b|+c/|c|+abc/|abc|
= 1+ 1- 1- 1
=0
(4) When there are two negative numbers and one positive number in the three numbers A, B and C,
a/|a|+b/|b|+c/|c|+abc/|abc|
=- 1- 1+ 1+ 1
=0
So a/|a|+b/|b|+c/|c|+abc/|abc| has three values, the maximum value is 4, the minimum value is -4, and the other value is 0.
So m=4 and n=-4.
Male (female) name
=4÷(-4-4)
=4÷(-8)
= - 1/2