(620-129*3)-128:4-2
1) 129*3 = 387
2) 620-387 = 233
3) 128:4 = 32
4) 233-32 = 201
5) 201-2 = 199
620-(129*3-128:4)-2
1) 129*3 = 387
2) 128:4 = 32
3) 387-32 = 355
4) 620-355 = 265
5) 265-2 = 263
620-129*3-128:(4-2)
1) 4-2 = 2
2) 129*3 = 387
3) 128:2 = 64
4) 620-387 = 233
5) 233-64 = 169