`A=2/15`
`B=3/4:5/8=6/5`
`C=15/6-1/3+1/6=7/3`
`D=5/12+16/12:34/3=5/12+2/17=109/204`
a) \(\dfrac{7}{15}+1=\dfrac{7}{15}+\dfrac{15}{15}=\dfrac{22}{15}\)
b) `4/7xx21/16:5/8=4/7xx21/16xx8/5=3/4xx5/8=6/5`
c) \(\dfrac{15}{8}-\dfrac{4}{9}\times\dfrac{6}{8}+\dfrac{1}{6}=\dfrac{15}{8}-\dfrac{1}{3}+\dfrac{1}{6}=\dfrac{45}{24}-\dfrac{8}{24}+\dfrac{4}{24}=\dfrac{45-8+4}{24}=\dfrac{41}{24}\)
d) \(\dfrac{5}{12}+\left(\dfrac{3}{4}+\dfrac{2}{3}\right):\dfrac{34}{3}=\dfrac{5}{12}+\dfrac{17}{12}\times\dfrac{3}{34}=\dfrac{5}{12}+\dfrac{1}{8}=\dfrac{13}{24}\)
A) 7/15+ 1=...\(\dfrac{7}{15}+\dfrac{15}{15}=\dfrac{7+15}{15}=\dfrac{22}{15}\)...
B) 4/7x 21/16: 5/8=...\(\dfrac{4}{7}.\dfrac{21}{16}.\dfrac{8}{5}=\dfrac{4.21.8}{7.16.5}=\dfrac{2.2.7.3.8}{7.8.2.5}=\dfrac{6}{5}\)....
C) 15/8- 4/9x 6/8+ 1/6=...\(\dfrac{15}{8}-\left(\dfrac{4}{9}.\dfrac{5}{8}\right)+\dfrac{1}{6}=\dfrac{15}{8}-\left(\dfrac{4.5}{9.8}\right)+\dfrac{1}{6}\\ =\dfrac{15}{8}-\left(\dfrac{4.5}{9.4.2}\right)+\dfrac{1}{6}=\dfrac{15}{8}-\dfrac{5}{18}+\dfrac{1}{6}\\ =\dfrac{135}{72}-\dfrac{20}{18}+\dfrac{12}{72}=\dfrac{135-20+12}{72}=\dfrac{127}{72}\)
D) 5/12+ ( 3/4+ 2/3 ) : 34/3=.\(\dfrac{5}{12}+\left(\dfrac{9}{12}+\dfrac{8}{12}\right).\dfrac{3}{34}=\dfrac{5}{12}+\dfrac{15}{12}.\dfrac{3}{34}\\ =\dfrac{5}{12}+\dfrac{15.3}{12.34}=\dfrac{5}{12}+\dfrac{15.3}{3.4.34}=\dfrac{5}{12}+\dfrac{15}{136}\\ =\dfrac{170}{408}+\dfrac{45}{408}=\dfrac{215}{408}\)
