Question

tinh nhanh 

Answer 1

tính thuận tiện hay bình thường :))

Answer 2

\(\dfrac{23}{8}-\dfrac{27}{20}+\dfrac{17}{8}-\dfrac{7}{20}\\ =\left(\dfrac{23}{8}+\dfrac{17}{8}\right)-\left(\dfrac{27}{20}+\dfrac{7}{20}\right)\\ =\dfrac{40}{8}-\dfrac{34}{20}\\ =5-\dfrac{17}{10}\\ =\dfrac{50}{10}-\dfrac{17}{10}\\ =\dfrac{33}{10}\)

Answer 3

Answer 4

23/8-17/8+27/20-7/20=6/8+20/20= 30/40+40/40=70/40

 

Answer 5

23/ 8−27/20+17/8−7/20=(23/8+17/8)−(27/20+7/20)=40/8−34/20=5−17/10=50/10−17/10=33/10