feat: Add explanation for the output of parseInt with different inputs

Questions-Answers/77.parseInt-2.md

@@ -0,0 +1,48 @@
+# 77. parseInt 2
+
+### Problem
+
+https://bigfrontend.dev/quiz/parseInt-2
+
+#
+
+### Problem Description
+
+What does the code snippet below output by `console.log`?
+
+```js
+console.log(parseInt(0.00001));
+console.log(parseInt(0.000001));
+console.log(parseInt(0.0000001));
+console.log(parseInt('0x12'));
+console.log(parseInt('1e2'));
+```
+
+#
+
+### Answer
+
+```js
+console.log(parseInt(0.00001)); // 0
+console.log(parseInt(0.000001)); // 0
+
+console.log(parseInt(0.0000001)); // 1
+// If the input value is less than or equal to 1e-7 (0.0000001), `parseInt()`
+// returns `1`.
+
+console.log(parseInt('0x12')); // 18
+// If the input string starts with `"0x"`, `radix` is assumed to be `16`.
+// (12)₁₆ = (1 × 16¹) + (2 × 16⁰) = (18)₁₀
+
+console.log(parseInt('1e2')); // 1
+// Since `"1e2"` is a string, `parseInt()` does not recognize exponential notation
+// and thus stops at the first letter.
+```
+
+#
+
+### Reference
+
+- [parseInt()](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/parseInt)
+
+- [parseInt('1e1') vs parseFloat('1e1')](https://stackoverflow.com/questions/31732983/parseint1e1-vs-parsefloat1e1)