a. If B and C are prime numbers and satisfy a + B + C + ABC = 99, then | 1a − 1b | + | 1b − 1c | + | 1c − 1a|=______ .

a. If B and C are prime numbers and satisfy a + B + C + ABC = 99, then | 1a − 1b | + | 1b − 1c | + | 1c − 1a|=______ .

If a, B, C are all odd numbers, then ABC is also odd numbers, then a + B + C + ABC is even numbers, which contradicts a + B + C + ABC = 99, ∵ a, B, C must have an even number, and ∵ a, B, C must be prime numbers, ∵ a, B, C must have an even number is 2, let a = 2, then B + C + 2BC = 97, similarly, if B, C are all odd numbers, then BC is odd