Fix error of BigInt

Author: leviding

1-js/02-first-steps/05-types/article.md

@@ -66,7 +66,7 @@ We'll see more about working with numbers in the chapter <info:number>.
 
 ## BigInt
 
-In JavaScript, the "number" type cannot represent integer values larger than <code>(2<sup>53</sup>-1)</code> (that's `9007199254740991`), or less than <code>-(-2<sup>53</sup>-1)</code> for negatives. It's a technical limitation caused by their internal representation.
+In JavaScript, the "number" type cannot represent integer values larger than <code>(2<sup>53</sup>-1)</code> (that's `9007199254740991`), or less than <code>-(2<sup>53</sup>-1)</code> for negatives. It's a technical limitation caused by their internal representation.
 
 For most purposes that's quite enough, but sometimes we need really big numbers, e.g. for cryptography or microsecond-precision timestamps.