7 12 · 9 + 7 115
a) 12,(7) = 12 ------- = ------------------ = -----------
9 9 9
126- 12 114
b) 0,12(6) = ------------ = -------
900 900
312 - 3 309 1 · 990+ 309 990 + 309 1299
c)1,3(12) = 1 ----------- = 1 ---------- = ------------------- = --------------- = --------
990 990 990 990 990