Large numbers are an abstract thing. Humans can grasp what 5, 10 or 20 of something look like. 50 of something is harder to comprehend and at 100 it becomes a wild guess.
During my minor Visualising information we were given the task to make people understand how big one billion is. I started small, using grains of rice as unit. This allowed me to create equations we’re all familiar with and can comprehend, like bowls of rice and a stadium full of people. Using a visual style that focusses on content I created a poster that explains how big one billion is.