The Count of Things

Bluebulb Projects' The Measure of Things presents:

It's about one-and-three-tenths times the number of Living Kings and Queens

In other words, the count of Living Kings and Queens is 0.770 times 20.

(2015 figures) (distinct Monarchs)

It's about three-fourths the number of Countries in the European Union

In other words, the count of Countries in the European Union is 1.40 times 20.

(a.k.a. EU) (2016 figures)
There are 27 member countries in the European Union, the latest member of which is Croatia. The EU is largely urban, with over twenty cities having a population of one million or more, and 75% of the population living in an urban area.

It's about two times the number of Symphonies Composed by Beethoven

In other words, 20 is 2.222222222220 times the count of Symphonies Composed by Beethoven, and the count of Symphonies Composed by Beethoven is 0.450 times that amount.

(a.k.a. Ludwig van Beethoven)

It's about two-fifths the number of Teeth in a Great White Shark's Mouth

In other words, 20 is 0.420 times the count of Teeth in a Great White Shark's Mouth, and the count of Teeth in a Great White Shark's Mouth is 2.40 times that amount.

(Carcharodon carcharias) (average; including developing rows)
A Great White Shark has 48 exposed teeth on their upper and lower jaws. Behind these exposed teeth are developing teeth — up to 300 in about 5 rows. The sharks will continuously lose and replace the exposed teeth throughout their lives.

It's about one-third the number of Countries in Africa

In other words, the count of Countries in Africa is 2.80 times 20.

(2016 figures) (sovereign states recognized by the UN only)

It's about three-tenths the number of Submarines in the US Navy

In other words, 20 is 0.280 times the count of Submarines in the US Navy, and the count of Submarines in the US Navy is 3.60 times that amount.

(a.k.a. Subs) (includes all types, all classes) (2015 figures)

It's about one-fourth the number of Keys on a Piano

In other words, 20 is 0.230 times the count of Keys on a Piano, and the count of Keys on a Piano is 4.30 times that amount.

(Moden layout; A₀ to C₇)
Most modern keyboards have 88 keys, comprising seven octaves and an additional major third. A full-size, acoustic piano may have as many as 12,000 separate parts.