diff --git a/1-js/02-first-steps/09-comparison/article.md b/1-js/02-first-steps/09-comparison/article.md
index a69317fee..a24af5688 100644
--- a/1-js/02-first-steps/09-comparison/article.md
+++ b/1-js/02-first-steps/09-comparison/article.md
@@ -212,5 +212,5 @@ Why did we go over these examples? Should we remember these peculiarities all th
 - Comparison operators return a boolean value.
 - Strings are compared letter-by-letter in the "dictionary" order.
 - When values of different types are compared, they get converted to numbers (with the exclusion of a strict equality check).
-- The values `null` and `undefined` equal `==` each other and do not equal any other value.
+- The values `null` and `undefined` are equal `==` to themselves and each other, but do not equal any other value.
 - Be careful when using comparisons like `>` or `<` with variables that can occasionally be `null/undefined`. Checking for `null/undefined` separately is a good idea.
diff --git a/1-js/05-data-types/04-array/article.md b/1-js/05-data-types/04-array/article.md
index e71e86a5b..629a7c77f 100644
--- a/1-js/05-data-types/04-array/article.md
+++ b/1-js/05-data-types/04-array/article.md
@@ -100,7 +100,7 @@ Let's say we want the last element of the array.
 
 Some programming languages allow the use of negative indexes for the same purpose, like `fruits[-1]`.
 
-Although, in JavaScript it won't work. The result will be `undefined`, because the index in square brackets is treated literally.
+However, in JavaScript it won't work. The result will be `undefined`, because the index in square brackets is treated literally.
 
 We can explicitly calculate the last element index and then access it: `fruits[fruits.length - 1]`.
 
diff --git a/1-js/09-classes/06-instanceof/article.md b/1-js/09-classes/06-instanceof/article.md
index f9db989ca..00aee3376 100644
--- a/1-js/09-classes/06-instanceof/article.md
+++ b/1-js/09-classes/06-instanceof/article.md
@@ -55,7 +55,7 @@ The algorithm of `obj instanceof Class` works roughly as follows:
     For example:
 
     ```js run
-    // setup instanceOf check that assumes that
+    // set up instanceof check that assumes that
     // anything with canEat property is an animal
     class Animal {
       static [Symbol.hasInstance](obj) {
@@ -68,7 +68,7 @@ The algorithm of `obj instanceof Class` works roughly as follows:
     alert(obj instanceof Animal); // true: Animal[Symbol.hasInstance](obj) is called
     ```
 
-2. Most classes do not have `Symbol.hasInstance`. In that case, the standard logic is used: `obj instanceOf Class` checks whether `Class.prototype` is equal to one of the prototypes in the `obj` prototype chain.
+2. Most classes do not have `Symbol.hasInstance`. In that case, the standard logic is used: `obj instanceof Class` checks whether `Class.prototype` is equal to one of the prototypes in the `obj` prototype chain.
 
     In other words, compare one after another:
     ```js