Question

calcule:
a) (3.10^12).(4.10^9)
b) (3.10^12):(4.10^9)
c) (2.10^0) + (1.10^1)
d) (2.10^ -2).(3.10^2) / (1,5.10^0).(40.10^ -1)
e) (5.10^ -2).(0,3.10^2) / (3.10^2).(0,0025)

Answer 1

a) $(3.10^1^2).(4.10^9)=12.10^2^1$

b) $(3.10^1^2):(4.10^9)= \frac{3}{4}.10^3=0,75 . 10^3$

c) $(2.10^0)+(1.10^1)= (2 . 1)+(1.10)= 2+10=12$

d) $\frac{(2.10^-^2).(3.10^2)}{(1,5.10^0).(40.10^-^1)}=$
   
    $\frac{6.10^0}{60.10^-^1} = \frac{6.1}{60. \frac{1}{10} }= \frac{6}{ \frac{60}{10} }=6: \frac{60}{10}=6. \frac{1}{6}= \frac{6}{6}=1$

$\frac{(5.10^-^2).(0,3.10^2)}{(3.10^2).(0,0025)}= \frac{1,5.10^0}{(3.10^2).(2,5.10^-^3)} = \frac{1,5 . 1}{7,5.10^-^1}=$

$= \frac{1,5}{ \frac{7,5}{10} }=1,5. \frac{10}{7,5}= \frac{15}{7,5}=2$