34.9 - 4.29 is done as follows:
34.90
- 4.29
---------
30. 61
---------
The working as follows:
step 1) First we subtract the decimal part. So, We take "1" carry from 9, so then we get, 10 - 9 = 1
step 2) Now, after taking "1" carry from 9, we are left with "8". So, 8-2 = 6
step 3) Simply now, 4-4 = 0
and 3 will remain as it is.
So, the result is 30. 61