Toán A) 3/5+-1/3 B) -2/13+-11/26 C) -2+-5/8 D)13/30-1/5 E) 2/21+-1/28 07/09/2021 By Faith A) 3/5+-1/3 B) -2/13+-11/26 C) -2+-5/8 D)13/30-1/5 E) 2/21+-1/28
Đáp án: \(a,\ \dfrac{4}{15}\\ b,\ \dfrac{-15}{26}\\ c,\ \dfrac{-21}{8}\\ d,\ \dfrac{7}{30}\\ e,\ \dfrac{5}{84}\) Giải thích các bước giải: \(a,\ \dfrac{3}{5}+\left (\dfrac{-1}{3} \right )=\dfrac{3.3}{5.3}+\dfrac{(-1).5}{3.5}=\dfrac{9}{15}+\dfrac{-5}{15}=\dfrac{4}{15}\\ b,\ \left (\dfrac{-2}{13} \right )+\left (\dfrac{-11}{26} \right )=\left (\dfrac{-2.2}{13.2} \right )+\left (\dfrac{-11}{26} \right )=\left (\dfrac{-4}{26} \right )+\left (\dfrac{-11}{26} \right )=\dfrac{-15}{26}\\ c,\ (-2)+\left (\dfrac{-5}{8} \right )=\left (\dfrac{-2.8}{8} \right )+\left (\dfrac{-5}{8} \right )=\left (\dfrac{-16}{8} \right )+\left (\dfrac{-5}{8} \right )=\dfrac{-21}{8}\\ d,\ \dfrac{13}{30}-\dfrac{1}{5}=\dfrac{13}{30}-\left (\dfrac{1.6}{5.6} \right )=\dfrac{13}{30}-\dfrac{6}{30}=\dfrac{7}{30}\\ e,\ \dfrac{2}{21}+\left (\dfrac{-1}{28} \right )=\left (\dfrac{2.4}{21.4} \right )+\left (\dfrac{-1.3}{28.3} \right )=\dfrac{8}{84}+\left (\dfrac{-3}{84} \right )=\dfrac{5}{84}\) chúc bạn học tốt! Trả lời
Đáp án: Giải thích các bước giải: a) 3/5 + (-1/3) =9/15 + (-5/15) =4/15 b)(-2/13) + (-11/26) =(-4/26) + (-11/26) =-15/26 c)(-2) + (-5/8) =(-16/8) + (-5/8) =-21/8 d)13/30 – 1/5 =13/30 – 6/30 =7/30 e)2/21 + (-1/28) =8/64 + (-3/64) =-21/64 Trả lời
Đáp án:
\(a,\ \dfrac{4}{15}\\ b,\ \dfrac{-15}{26}\\ c,\ \dfrac{-21}{8}\\ d,\ \dfrac{7}{30}\\ e,\ \dfrac{5}{84}\)
Giải thích các bước giải:
\(a,\ \dfrac{3}{5}+\left (\dfrac{-1}{3} \right )=\dfrac{3.3}{5.3}+\dfrac{(-1).5}{3.5}=\dfrac{9}{15}+\dfrac{-5}{15}=\dfrac{4}{15}\\ b,\ \left (\dfrac{-2}{13} \right )+\left (\dfrac{-11}{26} \right )=\left (\dfrac{-2.2}{13.2} \right )+\left (\dfrac{-11}{26} \right )=\left (\dfrac{-4}{26} \right )+\left (\dfrac{-11}{26} \right )=\dfrac{-15}{26}\\ c,\ (-2)+\left (\dfrac{-5}{8} \right )=\left (\dfrac{-2.8}{8} \right )+\left (\dfrac{-5}{8} \right )=\left (\dfrac{-16}{8} \right )+\left (\dfrac{-5}{8} \right )=\dfrac{-21}{8}\\ d,\ \dfrac{13}{30}-\dfrac{1}{5}=\dfrac{13}{30}-\left (\dfrac{1.6}{5.6} \right )=\dfrac{13}{30}-\dfrac{6}{30}=\dfrac{7}{30}\\ e,\ \dfrac{2}{21}+\left (\dfrac{-1}{28} \right )=\left (\dfrac{2.4}{21.4} \right )+\left (\dfrac{-1.3}{28.3} \right )=\dfrac{8}{84}+\left (\dfrac{-3}{84} \right )=\dfrac{5}{84}\)
chúc bạn học tốt!
Đáp án:
Giải thích các bước giải:
a) 3/5 + (-1/3)
=9/15 + (-5/15)
=4/15
b)(-2/13) + (-11/26)
=(-4/26) + (-11/26)
=-15/26
c)(-2) + (-5/8)
=(-16/8) + (-5/8)
=-21/8
d)13/30 – 1/5
=13/30 – 6/30
=7/30
e)2/21 + (-1/28)
=8/64 + (-3/64)
=-21/64