Đáp án+Giải thích các bước giải:

 a)

1/5-0,125-5/4

=1/5-1/8-5/4

=8/40-5/40-50/40

=3/40-50/40

=-47/40

b)

1,25-3/4+4/3

=5/4-3/4+4/3

=2/4+4/3

=1/2+4/3

=3/6+8/6

=11/6

c)

0,15-1/4+2/5

=3/20-1/4+2/5

=3/20-5/20+8/20

=6/20

=3/10

d)

5-3/4+1/5

=\frac{100}{20}-15/20+4/20

=\frac{100-15+4}{20}

=89/20

e)

1/4-0,3+4/3

=1/4-3/10+4/3

=15/60-18/60+80/60

=77/60

g)

-4/2+1/3-1/4

=-2+1/3-1/4

=-24/12+4/12-3/12

=-23/12

h)

1/2-0,4+1/5

=1/2-2/5+1/5

=1/2-(2/5-1/5)

=1/2-1/5

=5/10-2/10

=3/10

i)

4,2-4/5+1,2

=(4,2+1,2)-4/5

=5,4-4/5

=27/5-4/5

=23/5