đáp án là 3 

=3

75/100+18/21+19/32+1/4+3/21+13/32

= 18/21 + 3/21 + 19/32 + 13/32 + 75/100 + 1/4

= (18/21 + 3/21) + (19/32 + 13/32) + (3/4 + 1/4)

= 21/21 + 32/32 + 4/4

= 1 + 1 + 1

= 3

\(\frac{75}{100}+\frac{18}{21}+\frac{19}{32}+\frac{1}{4}+\frac{3}{21}+\frac{13}{32}\)

\(=\left(\frac{75}{100}+\frac{1}{4}\right)+\left(\frac{18}{21}+\frac{3}{21}\right)+\left(\frac{19}{32}+\frac{13}{31}\right)\)

\(=1+1+1\)

\(=3\)

Có những phân số chưa tối giản. Tuy nhiên vì đây là bài tính nhanh nên sẽ không rút gọn hết. Xíu quy đồng lại nữa :( Nên chọn lựa ra thôi.

\(\frac{75}{100}=\frac{3}{4}\)

Viết lại có: \(\frac{3}{4}+\frac{18}{21}+\frac{19}{32}+\frac{1}{4}+\frac{3}{21}+\frac{13}{32}\)

          \(=\left(\frac{3}{4}+\frac{1}{4}\right)+\left(\frac{18}{21}+\frac{3}{21}\right)+\left(\frac{19}{32}+\frac{13}{32}\right)\)

          \(=1+1+1\) 

          \(=3\)

= 3 nha banj

75/100+18/21+19/32+1/4+3/21+13/32

=(75/100+1/4)+(18/21+3/21)+(19/32+13/32)

=1+1+1=3

75/100+18/21+19/32+1/4+3/21+13/32

=1/4+75/100+19/32+13/32+3/21+18/21

=1+1+1=3

=(75/100+1/4)+(18/21+3/21)+(19/32+13/32)

=1+1+1

=3

lớp 4 mà 

\(=\dfrac{75:25}{100:25}+\dfrac{18}{21}+\dfrac{19}{32}+\dfrac{1}{4}+\dfrac{3}{21}+\dfrac{13}{32}\\ =\left(\dfrac{3}{4}+\dfrac{1}{4}\right)+\left(\dfrac{18}{21}+\dfrac{3}{21}\right)+\left(\dfrac{19}{32}+\dfrac{13}{32}\right)\\ =1+1+1=3\)

75/100+18/21+19/32+1/4+3/21+13/32=3 ban nhe!

ung ho nhe!

=3 nha bạn

nếu đung k mình nha

a ) 

75/100 + 18/21 + 19/32 + 1/4 + 3/21 + 13/32

= 3/4 + 18/21 + 19/321 + 1/4 + 3/21 + 13/32

= ( 3/4 + 1/4 ) + ( 18/21 + 3/21 ) + ( 19/32 + 13/32 )

= 1 + 1 + 1 

= 3

b ) 

4 và 2/5 + 5 và 6/9 + 2 và 3/4 + 1/4 + 1/3 + 3/5

= 22/5 + 51/9 + 11/4 + 1/4 + 1/3 + 3/5 

= ( 22/5 + 3/5 ) + ( 51/9 + 1/3 ) + ( 11/4 + 1/4 )

= 25/5 + 54/9 + 12/4

= 5 + 6 + 3 

= 14

a)\(\frac{75}{100}+\frac{18}{21}+\frac{19}{32}+\frac{1}{4}+\frac{3}{21}+\frac{13}{32}=\frac{3}{4}+\frac{18}{21}+\frac{1}{4}+\frac{19}{32}+\frac{3}{21}+\frac{13}{32}\)

\(=\left(\frac{3}{4}+\frac{1}{4}\right)+\left(\frac{18}{21}+\frac{3}{21}\right)+\left(\frac{19}{32}+\frac{13}{32}\right)\)

\(=1+1+1=3\)