a : 54 = x rest 53 ==>a = 54x + 53 |+1
a : 36 = y rest 35 ==> a = 36y + 35 | +1
a : 72 = z rest 71 ==> a = 72×z + 71 |+1
a + 1 = 54×(x + 1)
a + 1 = 36×(y+1)
a + 1 = 72×(z+1)
a + 1 = c.m.m.m.c (54;36;72)
54 = 2×3^3
36 = 2^2 × 3^2
72 = 2^3 × 3^2
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2^3 × 3^3 = 8 × 27 = 216
a + 1 = 216 ==> a = 215
