Bài 1:thực hiện phép tính
a) 12-3+5=14
b) 80:10x4=32
c) 100:10x2=20
d) 66-6:2=63
e) 12+8x4=44
f) 34+66:6=45
Bài 3
a)21 x 6 + 18 x 6 + 6 x 61
=6 x ( 21 + 18 + 61)
=6 x 100
= 600
b)1078 x 25 - 25 : 35 - 43 x 25
=25 x (1078 - 35 - 43)
=25 x 1000
=25000
d)49 + 27 + 87 + 53 + 51 + 13 + 71
=(49 + 51) + (27 + 53) + (87 + 13) + 71
=100 + 80 + 100 + 71
=180 + 171
=351
e)(132 + 39) - 132
=(132 - 132) + 39
=0 + 39
=39
f) 548 - (148 + 90)
=(548 - 148) + 90
=400 + 90
= 490
g) 23 + 123 + 77 + 877
=(23 + 77) + (123 + 877)
=100 + 1000
= 1100
h) 25 x 122 x 4 x 10
=(25 x 4) x (122 x 10)
=100 x 1220
= 122000
i)460 : (5 x 23)
=(460 : 23) x 5
=20 x 5
= 100