All numbers are 64-bit floats (IEEE 754). bigint for huge integers.

• no separate int type — 1 and 1.0 are the same
• NaN = Not a Number; NaN !== NaN
• Infinity and -Infinity exist
• floating point is imprecise: 0.1 + 0.2 !== 0.3
• parse with Number(), parseInt(), parseFloat()

See examples/.

Write round2(n) returning a number rounded to 2 decimals.