Question

Answer 1

a: =100x21=2100

b: =27/45-25/45=2/45

c: \(S=\left(\dfrac{27}{23}-\dfrac{4}{23}\right)+\left(-\dfrac{5}{21}-\dfrac{16}{21}\right)+\dfrac{1}{2}=\dfrac{1}{2}\)

Answer 2

a) 25 . (-3) . 4 . (-7)

= -75 . -28

= 2100

b) 3/5 + -5/9

= 2/45

Answer 3

a) 25.(-3).4.(-7) = 2100

b) \(\dfrac{3}{5}+\dfrac{5}{9}=\dfrac{52}{45}\)

c) \(S=\dfrac{27}{23}+\dfrac{-5}{21}-\dfrac{4}{23}+\dfrac{-16}{21}+\dfrac{1}{2}=\dfrac{41}{42}\)

Answer 4

a)25.(-3).4.(-7)

=(25.4).(-3).(-7)

=100.(-3).(-7)

=(-300).(-7)

=2100

b)\(\dfrac{3}{5}\)+\(\dfrac{-5}{9}\)

=\(\dfrac{27}{45}\)+\(\dfrac{-25}{45}\)

=\(\dfrac{2}{45}\)

c)S=\(\dfrac{27}{23}\)+\(\dfrac{-5}{21}\)-\(\dfrac{4}{23}\)+\(\dfrac{-16}{21}\)+\(\dfrac{1}{2}\)

S=(\(\dfrac{27}{23}\)-\(\dfrac{4}{23}\))+(\(\dfrac{-5}{21}\)+\(\dfrac{-16}{21}\))+\(\dfrac{1}{2}\)

S=1+(-1)+\(\dfrac{1}{2}\)

S=\(\dfrac{1}{2}\)