const num1 = 9007199254740992n;
const num2 = 1n;

const result1 = num1 + num2;
const result2 = Number(num1) + Number(num2);
const result3 = num1 + BigInt(1);
const result4 = String(num1) + String(num2);

console.log(typeof result2 === typeof result1, result1 === result3, result4);