Full form of BODMAS is

B -> Bracket

O -> of

D -> Division

M -> Multiplication

A -> Addition

S -> Subtraction

We solver the qoestion based on BODMAS

Ex1: 20 + 21/3 * 2

Here, first we solve division operation, then multiplication and the addition operation.

    20 + 7 * 2

= 20 + 14

= 34

Ex2:  17 + (8 - 5) * 5

Fiesr we solve bracket, then multiplication and at last addition operation

       = 17 + 3 * 5
 
       = 17 + 15

       = 32

Ex3: 25 - 48 / 6 + 12 * 2

     = 25 - 8 + 12 * 2          (Simplifying division 48 / 6 = 8)

     = 25 - 8 + 24               (Simplifying multiplication 12 * 2 = 24)

     = 17 + 24                    (Simplifying subtraction 25 - 8 = 17)

     = 41                            (Simplifying addition 17 + 24 = 41)

Hope you got the point.