a, 204 - 84.12
= 12.17 - 12.84
= 12 . (17-84)
= 12 . (-67)
= -804
b, 15.23 + 4.32 - 5.7
= 15.8 + 4.9 - 5.7
= 120 + 36 - 35
= 120 +1
= 121
c, 56 : 53 + 23 . 22
= 56-3 + 23+2
= 53 + 25
= 125 - 32
= 93
d, 164.53 + 47.164
= 164.(53 + 47)
= 164 . 100
= 16400
Vậy ...
Nhớ line cho mình nhé!