Help please due later today.....

Answer:
a- the sum = 0.0031
b- the fly is 0.0013 grams heavier
Answer:
Step-by-step explanation:
a).
2.2 × [tex]10^{-3}[/tex] + 9 × [tex]10^{-4}[/tex] =
2.2 × [tex]10^{-3}[/tex] + 0.9 × [tex]10^{-3}[/tex] =
( 2.2 + 0.9 ) × [tex]10^{-3}[/tex] = 3.1 × [tex]10^{-3}[/tex]
b).
2.2 × [tex]10^{-3}[/tex] - 9 × [tex]10^{-4}[/tex] =
2.2 × [tex]10^{-3}[/tex] - 0.9 × [tex]10^{-3}[/tex] =
( 2.2 - 0.9 ) × [tex]10^{-3}[/tex] = 1.3 × [tex]10^{-3}[/tex]