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\(\dfrac{8}{13}+\dfrac{4}{9}+\dfrac{1}{3}+\dfrac{5}{13}+3\)
\(=1+\dfrac{7}{9}+3\)
\(=4+\dfrac{7}{9}=\dfrac{43}{9}\)
\(\frac{1}{5}+\frac{5}{7}+\frac{1}{8}+\frac{13}{8}+\frac{4}{5}+\frac{4}{7}\)
\(=\left(\frac{1}{5}+\frac{4}{5}\right)+\left(\frac{5}{7}+\frac{4}{7}\right)+\left(\frac{1}{8}+\frac{13}{8}\right)\)
\(=1+\frac{9}{7}+\frac{7}{4}\)
\(=\frac{28}{28}+\frac{36}{28}+\frac{49}{28}\)
\(=\frac{113}{28}\)
Ai k mik mik k lại
Bài 1 : Tính bằng cách thuận tiện
A = 3/13 x 5/7 + 2/13 x 3/7
= 2/13 + 1/13 x 5/7 + 2/13 x 3/7
= 2/13 x 72/91 + 2/13 x 3/7
= 2/13 x ( 72/91 + 3/7 )
= 2/13 x 37/24
= 37/156.
B = 21/22 x 17/8 + 21/8 x 7/22
= 21/22 x 17/8 + 17/8 + 4/8 x 7/22
= 21/22 x 17/8 + 17/8 x 7/44
= ( 21/22 + 7/44 ) x 21/22
= 31/44 x 21/22
= 651/968.
Chúc bạn học tốt!!!
AI lấy đêf kiểm tra toán giữa kì 1 không
ai nhanh thì mình sẽ cho
\(\frac{8}{13}+\frac{4}{9}+\frac{1}{3}+\frac{5}{13}+3\)
\(=\left(\frac{8}{13}+\frac{5}{13}\right)+\left(\frac{4}{9}+\frac{1}{3}\right)+3\)
\(=1+\frac{7}{9}+3\)
\(=\frac{43}{9}\)
a)\(\frac{8}{13}+\frac{4}{9}+\frac{1}{3}+\frac{5}{13}+\)\(3\)
\(=\left(\frac{8}{13}+\frac{5}{13}\right)+\left(\frac{4}{9}+\frac{1}{3}\right)+3\)
\(=\frac{13}{13}+\frac{7}{9}+3\)
\(=1+\frac{4}{9}+3\)
\(=4\frac{4}{9}\)
b)\(\frac{8}{5}\)X\(\frac{4}{7}+\frac{4}{7}\)X\(\frac{2}{5}-1\)
\(=\left(\frac{8}{5}+\frac{2}{5}\right)\)X\(\frac{4}{7}-1\)
\(=1\)X\(\frac{4}{7}-1\)
\(=\frac{3}{7}\)
A) 8/13+4/9+1/3+5/13+3=
=(8/13+5/13)+(4/9+1/3)+3
= 13/13+(4/9+3/9)+3
=13/13+7/9+3
=13/13+(7/9+3)
=13/13+(7/9+27/9)
13/13+34/9=117/117+442/117=559/117
B)8/5*4/7+4/7*2/5-1
= 4/7 * (8/5+2/5)-1
= 4/7* 10/5-1
= 4/7 *2-1
=(4/7*2)-1
=8/7 -1 =8/7 - 7/7
= 1/7