Răspuns:
[tex]13 {}^{(7)} = 1 \times 7 {}^{0} + 3 \times {7}^{1} \\ = 1 \times 1 + 3 \times 7 \\ 1 + 21 = 22[/tex]
[tex]42 {}^{(6)} = 4 \times {6}^{0} + 2 \times {6}^{1} \\ = 4 \times 1 + 2 \times 6 \\ = 4 + 12 = 16[/tex]
[tex]32 {}^{(5)} = 3 \times 5 {}^{0} + 2 \times 5 {}^{1} \\ = 3 \times 1 + 2 \times 5 \\ = 3 + 10 = 13[/tex]
[tex]13 {}^{(7)} + 42 {}^{(6)} + 32 {}^{(5)} = 22 + 16 + 13 \\ = 38 + 13 = 51[/tex]