-5/10+3 14/15=20,433

Here’s how it works if you mean -5/10 + (3 14/15):

-5/10 = -1/2 3 14/15 = 3 + 14/15 = 59/15

Sum: -1/2 + 59/15 Common denominator 30: (-15 + 118)/30 = 103/30

So the value is 103/30 = 3 and 13/30 ≈ 3.433333...

If you intended 20,433 (either 20.433 with decimal comma or 20433 with thousands separator), that is not equal to the expression above. The left side equals 3.433... (not 20.433 or 20433).

If you meant a different interpretation (different grouping or operators), tell me and I’ll recompute.