Question

tính bằng hai cách

a. 2\(\dfrac{1}{4}\) + 1\(\dfrac{1}{6}\)

b. 7\(\dfrac{1}{8}\) - 5\(\dfrac{3}{4}\)

c. 4 - 2\(\dfrac{6}{7}\)

Answer 1

Mik làm nhé:

cách 1:

a, \(2\dfrac{1}{4}+1\dfrac{1}{6}\)

= \(\dfrac{9}{4}+\dfrac{7}{6}\)

= \(\dfrac{27}{12}+\dfrac{14}{12}\)

= \(\dfrac{27+14}{12}\)

= \(\dfrac{41}{12}=3\dfrac{5}{12}.\)

b, \(7\dfrac{1}{8}-5\dfrac{3}{4}\)

= \(\dfrac{57}{8}-\dfrac{23}{4}\)

=\(\dfrac{57}{8}-\dfrac{46}{8}\)

= \(\dfrac{57-46}{8}\)

= \(\dfrac{11}{8}=1\dfrac{3}{8}.\)

c, \(4-2\dfrac{6}{7}\)

= \(4-\dfrac{20}{7}\)

= \(\dfrac{28}{7}-\dfrac{20}{7}\)

= \(\dfrac{28-20}{7}\)

= \(\dfrac{8}{7}=1\dfrac{1}{7}.\)

CHÚC BN HỌC GIỎI!!! :) :) :)

Đừng quên bình luận nếu bài tớ sai nhé!!!

Answer 2

Cách 2 thì mik chưa học nên ko biết làm, xin lỗi bn nha!!!