Question

tính bằng cách thuận tiện nhất :

a) 7/11 + 3/4 + 4/11 + 1/4

b)72/99 - 28/99 - 14/99

c)69,78 + 35,97 + 30,22

d)83,45 - 30,98 - 42,47

Answer 1

a) 7/11+3/4+4/11+1/4

=(7/11+4/11)+(3/4+1/4)

=     1           +    1

=          2.

b) 72/99-28/99-14/99

=72/99-(28/99+14/99)

=72/99-      42/99

=     30/99=10/33.

c) 69,78+35,97+30,22

=(69,78+30,22)+35,97

=      100          +35,97

=                 135,97.

d) 83,45-30,98-42,47

=83,45-(30,98+42,47)

=83,45-      73,45

=        10.

Answer 2

a) 2

b) 10/33

c) 135,97

d) 10

Answer 3

a: (7/11+4/11)+(3/4+1/4)

=11/11+4/4

=1+1=2

b: 72/99-28/99-14/99

=72/99-(28/99+14/99)

=72/99-42/99

=30/99

=10/33

c: 69,78+35,97+30,22

=(69,78+30,22)+35,97

=100+35,97

=135,97

d :83,45-(30,98+42,47)

=83,45-73,45

=10