1/
a, 4 . 73 . 9 + 6 . 17 . 6 + 2 . 18 . 10
= (4.9).73+(6.6).17+(2.18).10
=36.73+36.17+36.10
=36.(73+17+10)
=36.100
=3600
b, 79 . 64 + 36 . 79 - 2800 : 7
=79.(64+36)-2800:7
=79.100-400
=7900-400
=7500
2/
a/ A = 123 . 123 và B = 121.124
A = 123 . 123
=123.(121+2).123.121+123.2
B = 121.124
=121.(123+1).121.123+121.1
Vì 123.2 > 123.1
⇒ A > B