Numerele care impartite la 9 dau catul 13 sunt numerele de forma: 9*13 si 9*13+n; n</= cu 9
Exemplu: 9*13+3=120; 9*13+7=124
a : 9 = 13 rest 0
a = 13 × 9 + 0
a = 117 + 0
a = 117
b : 9 = 13 rest 1
b = 13 × 9 + 1
b = 117 + 1
b = 118
c : 9 = 13 rest 2
c = 13 × 9 + 2
c = 117 + 2
c = 119
d : 9 = 13 rest 3
d = 13 × 9 + 3
d = 117 + 3
d = 120
e : 9 = 13 rest 4
e = 13 × 9 + 4
e = 117 + 4
e = 121
f : 9 = 13 rest 5
f = 13 × 9 + 5
f = 117 + 5
f = 122
g : 9 = 13 rest 6
g = 13 × 9 + 6
g = 117 + 6
g = 123
h : 9 = 13 rest 7
h = 13 × 9 + 7
h = 117 + 7
h = 124
i : 9 = 13 rest 8
i = 13 × 9 + 8
i = 117 + 8
i = 125
