Ballpark — April 10, 2026
Answers to that day's 5 daily estimation questions.
Population of Tokyo metro area
37.3 million people
The metro area includes Yokohama, Kawasaki, and Chiba.
Brains an octopus has
9 brains
A central brain plus a mini-brain in each arm.
Bones in a shark
0 bones
Cartilage is lighter and more flexible than bone.
Pairs of ribs in a human body
12 pairs
Most people have 12 pairs of ribs.
Planets in the solar system
8 planets
The count dropped to eight after 2006.