Subtracting a number is the same as adding its opposite. Use this understanding to complete each of the equations below.

Enter numbers to evaluate ‐9−(‐12).

‐9−(‐12)= ‐9 + =

Enter numbers to evaluate ‐9−12.

‐9−12= ‐9 + ? =

Planet earth has a mass of 5.9726x10²⁴ kg.then: 5.9726x10²⁴ kg=100% of the total earth mass.if the water´s mass=5x10-4 % of the total mass, we can solve this problem by the rule of three.5.9726x10²⁴ %*10⁻⁴ %x=(5.9726x10²³ kg)(5*10⁻⁴  %) / 100 %=2.9863x10¹⁹ kganswer:   the mass of the planet´s water would be   2.9863 x 10¹⁹ kg.