The numbers I have in my Anki deck, selected for how likely I am to find practical use of them:
total # hours in a year — 8760
${{c1::200}}k/year = ${{c2::100}}/hour
${{c1::100}}k/year = ${{c2::50}}/hour
# of hours in a working year — 2,000 hours
miles per time zone — ~1,000 miles
california top-to-bottom — 900 miles
US coast-to-coast — 3,000 miles
equator circumference — (before you show the answer, i always find it fun that i can quickly get an approximation by multiplying the # of time zones by the # of miles per time zone!) ||25,000|| miles
US GDP in 2022 — $25 trillion
google’s profit in 2022 — $60 billion
total US political spending per election — ~$5 billion
(interlude — i want to point out that, with 4 total cards, i can now translate between fahrenheit and celsius for most of my use-cases. neat!)
how old is the earth? — 4.5 billion years old
when did the dinosaurs go extinct? — 66mm years ago
novo nordisk market cap in 2025? — 2*10e11
apple market cap 2025? — 3.8*10e12
when was the Cambrian explosion? — 540 Ma
how deep is the earth’s crust? — 7–100 km // 5–60 mi
on a magnitude scale for earthquakes, each whole number change on the scale represents a change in energy release of [...]-fold — 32-fold
when did the first vertebrate-like creature (Tiktaalik) come onto land? — 375 Ma
how deep is the earth’s crust? — 7-100 km
taiwan pop in 2022? — 23 million
(roughly) how many neurons are in the human brain? — 10e11
what was the US unemployment rate in 2022? — 3.6%
when did eukaryotes evolve? — 2.1–2.7 Ga
give a range of reasonable estimates for the computing power needed to emulate a human mind? — 10e14 – 10e17
i’ve also found it useful to be able to reason with greater fluency about the numbers involved and their implications without needing to e.g. try to add up zeros or figure out what various prefixes mean at the same time. so, i’ve also added:
what quantity is denoted by “kilo”? — 1,000 / thousand / 10e3
what quantity is denoted by “mega”? — 1,000,000 / million / 10e6
what numerical quantity is “giga”? — billion / 10e9
The numbers I have in my Anki deck, selected for how likely I am to find practical use of them:
total # hours in a year — 8760
${{c1::200}}k/year = ${{c2::100}}/hour
${{c1::100}}k/year = ${{c2::50}}/hour
# of hours in a working year — 2,000 hours
miles per time zone — ~1,000 miles
california top-to-bottom — 900 miles
US coast-to-coast — 3,000 miles
equator circumference — (before you show the answer, i always find it fun that i can quickly get an approximation by multiplying the # of time zones by the # of miles per time zone!) ||25,000|| miles
US GDP in 2022 — $25 trillion
google’s profit in 2022 — $60 billion
total US political spending per election — ~$5 billion
median US salary in 2022 — $75k
LMIC’s GDP per capita in 2022 — $2.5k
world population in 2022 — 8 billion
NYC population in 2022 — 8 million
US population in 2022 — 330 million
some i’ve added since then:
how old is the universe? (i.e. when did the big bang happen?) — ~13.7 billion years ago
how long ago did the human/chimp lineage split? — ~6mm years ago
when did the homo sapiens species emerge? — ~300,000 ya
30 degrees Celsius → Fahrenheit — 86 degrees Fahrenheit
20 degrees Celsius → Fahrenheit — 68 degrees Fahrenheit
10 degrees Celsius → Fahrenheit — 50 degrees Fahrenheit
0 degrees Celsius → Fahrenheit — 32 degrees Fahrenheit
(interlude — i want to point out that, with 4 total cards, i can now translate between fahrenheit and celsius for most of my use-cases. neat!)
how old is the earth? — 4.5 billion years old
when did the dinosaurs go extinct? — 66mm years ago
novo nordisk market cap in 2025? — 2*10e11
apple market cap 2025? — 3.8*10e12
when was the Cambrian explosion? — 540 Ma
how deep is the earth’s crust? — 7–100 km // 5–60 mi
on a magnitude scale for earthquakes, each whole number change on the scale represents a change in energy release of [...]-fold — 32-fold
when did the first vertebrate-like creature (Tiktaalik) come onto land? — 375 Ma
how deep is the earth’s crust? — 7-100 km
taiwan pop in 2022? — 23 million
(roughly) how many neurons are in the human brain? — 10e11
what was the US unemployment rate in 2022? — 3.6%
when did eukaryotes evolve? — 2.1–2.7 Ga
give a range of reasonable estimates for the computing power needed to emulate a human mind? — 10e14 – 10e17
i’ve also found it useful to be able to reason with greater fluency about the numbers involved and their implications without needing to e.g. try to add up zeros or figure out what various prefixes mean at the same time. so, i’ve also added:
what quantity is denoted by “kilo”? — 1,000 / thousand / 10e3
what quantity is denoted by “mega”? — 1,000,000 / million / 10e6
what numerical quantity is “giga”? — billion / 10e9
(continue for giga, tera, peta, exa; and, deci, centi, milli, micro, nano, pico)
what is “10e3” in natural language? ↔ what is “one thousand” in scientific notation?
what is “10e6” in natural language? ↔ what is “one million” in scientific notation?
(continue for 10e9, 10e12, 10e15)