=6.28+(5.06+4.04)
=6.28+9. 1
= 15.38
32.8+3.02+ 17.2
=(32.8+ 17.2)+3.02
=50+3.02
=53.02
6.02+4.3+3.98
=(6.02+3.98)+4.3
= 10+4.3
= 14.3
5.85+ 1.89+4. 15
=(5.85+4. 15)+ 1.89
= 10+ 1.89
= 1 1.89