My three world population graphs

This is what I have been doing for maths,

Maths Graph

Graph 1 calculations:
1. how much more does Asia have in population than Africa if Asia has 60.7 % and Africa has? 14.6

2. what is the combine percentage of Oceania (0.5) and South America (5.7)?   

3. what is the combine percentage of Asia and Africa?

Graph 2 calculations:

1.What is the smallest density (4.24 mill) population plus the biggest density population (86.7 mill)?

2. How many people more people in Asia (86.7 mill) than Europe(70 mill)?

3. what does South (21.4 mill) plus North (22.9 mill)  America equal to?  

Graph 3 calculations:
1. What is the combined population of Mexico City (21163226) and Cairo (19439541)?

2. how much more dose Tokyo (35676000) have than Moscow (14837510)?

3. What is the combined population of Tokyo (35676000) and Cairo (19439541)?