a : 7 = cat si rest ; restul < 7
valorile restului pot fi : 0; 1; 2; 3; 4; 5; 6 .
catul ( c ) = restul ( r )
a = 7 × c + r = 7 × r + r = 8 × r
a =8 × 0; 8 × 1; 8×2; 8×3; 8×4; 8×5; 8×6 .
a = 0; 8; 16; 24; 32; 40; 48
Suma = 0 + 8 + 16 + 24 + 32 + 40 + 48 = 168
facem si verificarea :
0 : 7 = 0 rest 0
8 : 7 = 1 rest 1
16 : 7 = 2 rest 2
24 : 7 = 3 rest 3
32 : 7 = 4 rest 4
40 : 7 = 5 rest 5
48 : 7 = 6 rest 6 (adevarat)
