9 5/10 -- 1/23 = 43546 = 92146≅ 9.456522
Calculation steps
Conversion a mixed number to a improper fraction: 9 5/10 = 9 · 10 + 510= 9510
Subtract: 9510 - 123 = 95 · 2310 · 23 - 1 · 1023 · 10 = 2185230 - 10230 = 2185 - 10230 = 2175230 = 43546
The common denominator you can calculate as the least common multiple of the both denominators - LCM(10, 23) = 230