Tính nhanh : 50 - 51 + 40 - 42 + 30 - 31 + 60 ( 7,29 + 9,34 + 8,27 ) - (7,34 + 6,27 + 5,29 ) ...
Đọc tiếp
Tính nhanh : 50 - 51 + 40 - 42 + 30 - 31 + 60 ( 7,29 + 9,34 + 8,27 ) - (7,34 + 6,27 + 5,29 )
b) \(\left(7,29+9,34+8,27\right)-\left(7,34+6,27+5,29\right)\)
\(=\left(7,29-5,29\right)+\left(9,34-7,34\right)+\left(8,27-6,27\right)\)
\(=2+2+2=6\)
50-51+40-42+30-31+60=56
(7,29+9,34+8,27)-(7,34+6,27+5,29)
= 24,9 - 18,9
=43,8