E giải câu a được thôi ạ
A) = 891 + 109 + 359
= 1000 + 359
=1359
Mong c thông cảm
a: =891+109+359=1000+359=1359
b: =19/11+3/11+5/13=2+5/13=31/13
c: \(=\dfrac{17.8\left(3.7+5.7\right)-7.8\left(4.6+4.8\right)}{-0.3-0.3+3}=\dfrac{10\cdot9.4}{2.4}=\dfrac{94}{2.4}=\dfrac{235}{6}\)
d: \(=\dfrac{1}{5}+\dfrac{2}{5}+\dfrac{3}{5}+...+\dfrac{9}{5}=\dfrac{9\cdot\dfrac{10}{2}}{5}=9\)