13.58.4 + 32.26.2 + 52.10
= 52.58 + 32.52 + 52.10
= 52.(58+32+10)
= 52.100
=5200
b) 15.37.4 + 120.21 + 21.2.12
= 3.4.5.37 + 12.10.21 + 21.2.12
= 12.185 + 12.210 + 12.42
= 12 ( 185+210+42)
= 12.437
= 5244
c) 25.4 + 10.225 + 6.50
= 100 + 10.225 + 300
= 10.10+10.225+10.30
= 10(10+225+30)
= 10.265
= 2650
rùi giải tiếp