9+4+7=366329

It is solved as

9x4=36

9x7=63

these gives us first 2 sets now add both and subtract the last figure

36+63-7=92

now reverse it it will become 29

proof

5+5+3=251573

5x5=25

5x3=15

these give us 2515

now to calculate for last 73

25+15=40

and now subtract last digit that is

40-3=37

and reverse it will become 73