Question

A)7^8:[2^9-1^18]+7^8.[1^36-5^12].    B)[-0,75-1^4]:(-5)+1^15-(-1^5):(-3)

C)9^10-1^90-1^72-1^56-1^42-1^30-1^20-1^12-1^6-1^2                D)1+1^2.(1+2)+1^3.(1+2+3)+1^4.(1+2+3+4)+...+1^16.(1+2+3+4+...+16)

Answer 1

Dấu ^ là dấu gạch ngang của phản số nhé

Answer 2

a , \(\frac{7}{8}:\frac{1}{6}+\frac{7}{8}.\frac{-7}{18}\)  

  = \(\frac{21}{4}+\frac{-49}{144}=\frac{707}{144}\)

b, -1 : (-5) + \(\frac{1}{15}-\frac{-1}{15}\)

 = \(\frac{1}{5}+0=\frac{1}{5}\)

c, \(\frac{9}{10}-\frac{1}{10.9}-\frac{1}{9.8}-\frac{1}{8.7}-\frac{1}{7.6}-\frac{1}{6.5}-\frac{1}{5.4}-\frac{1}{4.3}-\frac{1}{3.2}-\frac{1}{2.1}\)

 =  \(\frac{9}{10}-\frac{10-9}{10.9}-\frac{9-8}{9.8}-\frac{8-7}{8.7}-\frac{7-6}{7.6}-\frac{6-5}{6.5}-\frac{5-4}{5.4}-\frac{4-3}{4.3}-\frac{3-2}{3.2}.\frac{2-1}{2.1}\)

 = \(\frac{9}{10}-1-\frac{1}{10}-1-\frac{1}{9}-1-\frac{1}{8}-1-\frac{1}{7}-1-\frac{1}{6}-1-\frac{1}{5}-1-\frac{1}{4}-1-\frac{1}{3}-1-\frac{1}{2}\)

 = \(\frac{9}{10}-\left(1+1+1+1+1+1+1+1+1\right)-\left(\frac{1}{10}+\frac{1}{9}+\frac{1}{8}+...+\frac{1}{2}\right)\)

= \(\frac{9}{10}-9-1,928=\frac{9}{10}-7,071=-6.171\)