base arithmetic conversation decimal to (+3)

Question

I've asked the question because I've never seen a base like that before. For example, $76_{10}$ = $(?)_{+3}$ . The issue is that what does $_{+3}$ stand for ?

Answer 1

I suppose that $76_{10}=(?)_{+3}$ means that you have to write the number given in basis $10$ in the new basis $3$. So you have to divide $76$ by the powers of $3$ : $$ 76 : 27 = 2 \quad 76-2\times 27=22 $$ $$ 22 : 9= 2 \quad 22-9 \times 2 = 4 $$ $$ 4 : 3= 1 \quad 4-3 \times 1 = 1 $$ $$ 1 : 1= 1 $$ and you have $76_{10}=2211_{3}$.