tính nhanh:
B = 7/18 .(-12/23 - 4/15) + 7/18 . (8/30 + 35/23)
Tính hợp lý
7/18 .(-12/23 - 4/15) + 7/18 . (8/30 + 35/23)
\(=\dfrac{7}{18}.\dfrac{-12}{23}-\dfrac{7}{18}.\dfrac{4}{5}+\dfrac{7}{18}.\dfrac{8}{30}+\dfrac{7}{18}.\dfrac{35}{23}\)
\(=\dfrac{7}{18}.\left(\dfrac{-12}{23}+\dfrac{35}{23}\right)+\dfrac{7}{18}.\left(\dfrac{4}{5}-\dfrac{8}{30}\right)\)
\(=\dfrac{7}{18}.1+\dfrac{7}{18}.\dfrac{8}{15}\)
\(=\dfrac{7}{18}+\dfrac{28}{135}\)
\(=\dfrac{161}{270}\)
tính nhanh:
B = 7/18 .(-12/23 - 4/15) + 7/18 . (8/30 + 35/23)
\(\frac{7}{18}.\left(\frac{-12}{23}-\frac{4}{15}\right)+\frac{7}{18}.\left(\frac{8}{30}+\frac{35}{23}\right)\)
\(\frac{7}{18}.\left(\frac{-12}{23}-\frac{4}{15}\right)+\frac{7}{18}.\left(\frac{8}{30}+\frac{35}{23}\right)\)
\(=\frac{7}{18}.\left(\frac{-12}{23}-\frac{4}{15}\right)+\frac{7}{18}.\left(\frac{4}{15}+\frac{35}{23}\right)\)
\(=\frac{7}{18}.\left(\frac{-12}{23}-\frac{4}{15}+\frac{4}{15}+\frac{35}{23}\right)\)
\(=\frac{7}{18}.[\left(\frac{-12}{23}+\frac{35}{23}\right)+\left(\frac{-4}{15}+\frac{4}{15}\right)]\)
\(=\frac{7}{18}.1+0\)
\(=\frac{7}{18}\)
_Chúc bạn học tốt_
1, Thực hiện phép tính ( tính hợp lý nếu có thể) A, -1/12+4/3 B,(-4/14-3/15)-(1/5-20/35- -1)7 C, 3/5+ -5/20+30/75+ -7/4 D, 5/6. -12/13 + 7/13 E, 2/-9 - 5/-36 - 1/4 F, 2/23 +-5/12+7/18+21/23+ -7/12
c) Ta có: \(\dfrac{3}{5}+\dfrac{-5}{20}+\dfrac{30}{75}+\dfrac{-7}{4}\)
\(=\dfrac{3}{5}+\dfrac{2}{5}+\dfrac{-1}{4}+\dfrac{-7}{4}\)
\(=1-2=-1\)
Giải:
a)-1/12+4/3=-1/12+16/12=15/12=5/4
b)(-4/14-3/15)-(1/5-20/35-(-1)).7
=-17/35-22/35.7
=-17/35-22/5
=-171/35
c)3/5+-5/20+30/75+-7/4
=3/5+-1/4+2/5+-7/4
=(3/5+2/5)+(-1/4+-7/4)
=1+-2
=-1
d)5/6.-12/14+7/13
=-5/7+7/13
=-16/91
e)2/-9-5/-36-1/4
=-1/12-1/4
=-1/3
f)2/23+-5/12+7/18+21/23+-7/12
=(2/23+21/23)+(-5/12+-7/12)+7/18
=1+-1+7/18
=7/18
Tính hợp lý:
\(A=1+\frac{-9}{16}.\frac{13}{27}+\frac{9}{16}.\frac{-14}{27}\)
\(B=\frac{7}{18}.\left(\frac{-12}{23}-\frac{4}{15}\right)+\frac{7}{18}.\left(\frac{8}{30}+\frac{35}{23}\right)\)
Làm đầy đủ các bước nha
tinh ho mk nhé
( 2 - 1/2 - 1/3 ) x ( 1 - 1/4 - 1/7 )
7/18 x ( -12/23 - 4/15 ) + 7/18 x ( 8/30 + 35/23 )
từng bước cho mình nhé đừng làm tắt đừng ghi kết quả mk sẽ tick
a 12 – 34 b 23 – 47 c 31 – 23 d 9 – 5 e 4 – 15 25 f 23 13 17 57 g 4 . 9 6 . 12 – 7 h 14 6 19 14 19 i 56 – 8. 27 7 j 8 5 . 2 – 3 6 k 4 . 3 125 . 25 8 l 9 6 . 3 – 4 7 m 45. 18 – 15 – 18. 45 – 15
Tách từng câu ra giùm, như này ai giải nổi:)))))
>; <; = ?
a) \(\dfrac{4}{7}\) \(\dfrac{6}{7}\) \(\dfrac{15}{23}\) \(\dfrac{12}{23}\) \(\dfrac{45}{60}\) \(\dfrac{3}{4}\)
b) \(\dfrac{8}{9}\) \(\dfrac{11}{18}\) \(\dfrac{13}{18}\) \(\dfrac{2}{3}\) \(\dfrac{27}{25}\) 1
a) \(\dfrac{4}{7}< \dfrac{6}{7}\)
\(\dfrac{15}{23}>\dfrac{12}{23}\)
\(\dfrac{45}{60}=\dfrac{3}{4}\)
b) \(\dfrac{8}{9}>\dfrac{11}{18}\)
\(\dfrac{13}{18}>\dfrac{2}{3}\)
\(\dfrac{27}{25}>1\)
tính :
1+2+3+4+5+6+7+8+9+10+12+14+16+18+20+23+26+29+30-29-19-9+50+55+15+25+35+45+65+75+85+95+1000000000000+99999999=?
dãy số dài như thế này dễ lẫn lắm bạn ạ