diff --git a/src/exo0/exo0.ts b/src/exo0/exo0.ts
index 7a7fc7c..dab5136 100644
--- a/src/exo0/exo0.ts
+++ b/src/exo0/exo0.ts
@@ -2,7 +2,7 @@
 // Composing computations with `pipe` and `flow`
 
 // Functional programming is all about composing small functions together like
-// lego bricks to build more and more complex computations.
+// Lego bricks to build more and more complex computations.
 //
 // Strictly speaking, composing two functions `f` and `g` means applying the
 // result of the first one to the second one. By applying this composition
diff --git a/src/exo1/exo1.ts b/src/exo1/exo1.ts
index 08ec470..9278168 100644
--- a/src/exo1/exo1.ts
+++ b/src/exo1/exo1.ts
@@ -20,24 +20,22 @@ export const divide = (a: number, b: number): number => {
 // Write the safe version (meaning it handles the case where b is 0) of `divide` with signature:
 // safeDivide : (a: number, b: number) => Option<number>
 //
-// HINT: Option has two basic contructors:
+// HINT: Option has two basic constructors:
 // - `option.some(value)`
 // - `option.none`
 
 export const safeDivide: (a: number, b: number) => Option<number> =
   unimplemented;
 
-
 // You probably wrote `safeDivide` using `if` statements and it's perfectly valid!
 // There are ways to not use `if` statements.
-// Keep in mind that extracting small functions out of pipes and using `if` statements in them 
+// Keep in mind that extracting small functions out of pipes and using `if` statements in them
 // is perfectly fine and is sometimes more readable than not using `if`.
 //
 // BONUS: Try now to re-write `safeDivide` without any `if`
 //
 // HINT: Have a look at `fromPredicate` constructor
 
-
 ///////////////////////////////////////////////////////////////////////////////
 //                                  EITHER                                   //
 ///////////////////////////////////////////////////////////////////////////////
diff --git a/src/exo2/exo2.ts b/src/exo2/exo2.ts
index 9624614..b6cd038 100644
--- a/src/exo2/exo2.ts
+++ b/src/exo2/exo2.ts
@@ -10,7 +10,7 @@ import { unimplemented } from '../utils';
 //                                   SETUP                                   //
 ///////////////////////////////////////////////////////////////////////////////
 
-// We are developping a small game, and the player can control either one of
+// We are developing a small game, and the player can control either one of
 // three types of characters, mainly differentiated by the type of damage they
 // can put out.
 
@@ -133,7 +133,7 @@ export const checkTargetAndShoot: (
 //                                  OPTION                                   //
 ///////////////////////////////////////////////////////////////////////////////
 
-// The next three function take a `Character` and optionally return the
+// The next three functions take a `Character` and optionally return the
 // expected damage type if the unit matches the expected character type.
 //
 // HINT: These functions represent the public API. But it is heavily
diff --git a/src/exo5/exo5.ts b/src/exo5/exo5.ts
index 7527eb3..36619ea 100644
--- a/src/exo5/exo5.ts
+++ b/src/exo5/exo5.ts
@@ -76,6 +76,7 @@ export const naiveGiveCurrencyOfCountryToUser = (
     task.map(getCountryCode),
     task.map(option.map(getCountryCurrency)),
   );
+
 // The result type of this method is: `Task<Option<Task<Currency>>>`
 // Not ideal, right? We would need to await the first `Task`, then check if it's
 // `Some` to get the `Task` inside and finally await the `Task` to retrieve the
@@ -103,7 +104,7 @@ export const getCountryCurrencyOfOptionalCountryCode: (
 // `Task<Option<Currency>>`
 //
 // HINT: You should be able to copy the pipe from naiveGiveCurrencyOfCountryToUser
-// and make only few updates of it. `task.chain` helper may be usefull.
+// and make only few updates of it. The `task.chain` helper may be useful.
 
 export const giveCurrencyOfCountryToUser: (
   countryNameFromUserMock: string,
@@ -123,6 +124,7 @@ export const giveCurrencyOfCountryToUser: (
 export const getCountryCodeOfCountryNames = (
   countryNames: ReadonlyArray<string>,
 ) => countryNames.map(getCountryCode);
+
 // As expected, we end up with a `ReadonlyArray<Option<CountryCode>>`. We know for
 // each item of the array if we have been able to find the corresponding country
 // code or not.
@@ -134,7 +136,7 @@ export const getCountryCodeOfCountryNames = (
 // Doing this allows you to stop the process if you have a `None` to tell the user
 // that some countries are not valid or move on with a `ReadonlyArray<CountryCode>>`
 // if all are valid.
-// Typewise, it means going from `ReadonlyArray<Option<CountryCode>>` to
+// Type-wise, it means going from `ReadonlyArray<Option<CountryCode>>` to
 // `Option<ReadonlyArray<CountryCode>>`
 // This is what traversing array is about.
 
@@ -208,7 +210,7 @@ export const performAsyncComputationInSequence: (
 // `Option<Task>` in our example)
 // Sometimes, you just have two nested containers that you want to 'invert'. It
 // can be because the order of containers is meaningful (like `Either<Option>`
-// and `Option<Either>`) because you got them from an external api, as
+// and `Option<Either>`) or because you got them from an external api, as
 // in the examples.
 // In that case, what you need is `sequence`, which you can find in the modules
 // that have `traverse`.
diff --git a/src/exo6/exo6.ts b/src/exo6/exo6.ts
index 6cac58a..7658b31 100644
--- a/src/exo6/exo6.ts
+++ b/src/exo6/exo6.ts
@@ -12,7 +12,7 @@ import { User } from './domain';
 // `Task` -> For async operation
 // `Either` -> For computations that may fail
 //
-// Keep in Mind, A ReaderTaskEither is nothing more than a Reader of a Task of an Either
+// Keep in mind, a ReaderTaskEither is nothing more than a Reader of a Task of an Either
 // type ReaderTaskEither<Env, Error, Value> = Reader<Env, Task<Either<Error, Value>>>
 //
 // The ReaderTaskEither module from fp-ts gives us some useful methods to manipulate it.
@@ -23,7 +23,6 @@ import { User } from './domain';
 // current context. In the following example, we need to fetch a user by its id
 // and then we want to return its capitalized.
 
-
 export const getCapitalizedUserName: (args: {
   userId: string;
 }) => ReaderTaskEither<
@@ -32,7 +31,7 @@ export const getCapitalizedUserName: (args: {
   string
 > = unimplemented;
 
-// Sometimes you will need to get multiple data before performing an operation
+// Sometimes you will need to get multiple data points before performing an operation
 // on them. In this case, it is very convenient to use the `Do` notation.
 //
 // The `Do` notation allows you to enrich the context step-by-step by binding
@@ -59,10 +58,10 @@ export const getConcatenationOfTheTwoUserNames: (args: {
 // only retrieve after performing some operations, in other words, operations
 // need to be sequential.
 // For example, if you want to fetch the best friend of a user you will have to
-// fetch the first user and then fetch its best friend.
+// first fetch the user and then fetch their best friend.
 // In this case, we will use `rte.bindW()` to use data of the current context
-// (the firstly fetched user) to perform a second operation (fetch its best friend)
-// and bind the return value to feed the context and use those data.
+// (the firstly fetched user) to perform a second operation (fetch their best friend)
+// and bind the return value to feed the context and use this data.
 
 export const getConcatenationOfTheBestFriendNameAndUserName: (args: {
   userIdOne: string;
diff --git a/src/exo7/exo7.ts b/src/exo7/exo7.ts
index e5a3915..b6999dc 100644
--- a/src/exo7/exo7.ts
+++ b/src/exo7/exo7.ts
@@ -14,7 +14,7 @@ import { unimplemented } from '../utils';
 // In fact, it can sometimes be helpful to think of `Set` as a special case
 // of `Map` where `Set<T>` is strictly equivalent to `Map<T, void>`.
 //
-// To manipulate these collections, we need often need to inform `fp-ts` on
+// To manipulate these collections, we often need to inform `fp-ts` on
 // how to uphold the properties outlined above (eg. how to determine whether
 // two elements or keys have the same value, how to combine values together
 // in case of key collision or how to order the values when converting back
@@ -43,7 +43,7 @@ export const numberArray: ReadonlyArray<number> = [7, 42, 1337, 1, 0, 1337, 42];
 
 export const numberSet: ReadonlySet<number> = unimplemented();
 
-// Convert `numberSet` back to an an array in `numberArrayFromSet`.
+// Convert `numberSet` back to an array in `numberArrayFromSet`.
 // You need to use the `ReadonlySet` module from `fp-ts` instead of the
 // JavaScript standard constructor.
 //
@@ -118,7 +118,7 @@ export const mapWithLastEntry: ReadonlyMap<number, string> = unimplemented();
 //   The `string` module may contain what you need ;)
 //
 // Bonus point:
-// Did you find something helpful in the `Semigroup` module that may have been
+// Did you find something in the `Semigroup` module that may have been
 // helpful in defining `mapWithLastEntry`?
 
 export const mapWithConcatenatedEntries: ReadonlyMap<number, string> =
@@ -135,7 +135,7 @@ export const odds = new Set([1, 3, 5, 7, 9]);
 // only include the odd numbers that are not prime.
 //
 // HINT:
-// - Be mindful of the order of operands for the operator you will chose.
+// - Be mindful of the order of operands for the operator you will choose.
 
 export const nonPrimeOdds: ReadonlySet<number> = unimplemented();
 
@@ -151,7 +151,7 @@ export type Analytics = {
   views: number;
 };
 
-// These example maps are voluntarily written in a non fp-ts way to not give
+// These example Maps are voluntarily written in a non fp-ts way to not give
 // away too much obviously ;)
 //
 // As an exercise for the reader, they may rewrite those with what they've
@@ -173,14 +173,14 @@ export const pageViewsB = new Map(
   ].map(entry => [entry.page, entry]),
 );
 
-// Construct the map with the total page views for all the pages in both sources
+// Construct the `Map` with the total page views for all the pages in both sources
 // of analytics `pageViewsA` and `pageViewsB`.
 //
 // In case a page appears in both sources, their view count should be summed.
 
 export const allPageViews: ReadonlyMap<string, Analytics> = unimplemented();
 
-// Construct the map with the total page views but only for the pages that
+// Construct the `Map` with the total page views but only for the pages that
 // appear in both sources of analytics `pageViewsA` and `pageViewsB`.
 
 export const intersectionPageViews: ReadonlyMap<string, Analytics> =
diff --git a/src/exo8/exo8.test.ts b/src/exo8/exo8.test.ts
index 6006dca..f025a87 100644
--- a/src/exo8/exo8.test.ts
+++ b/src/exo8/exo8.test.ts
@@ -1,8 +1,8 @@
 import { either, reader, readerTaskEither as rte } from 'fp-ts';
 import { pipe } from 'fp-ts/function';
 import {
-  apEitherK as rteApEitherK,
-  apEitherKW as rteApEitherKW,
+  apSEitherK as rteApSEitherK,
+  apSEitherKW as rteApSEitherKW,
   bindEitherK as rteBindEitherK,
   bindEitherKW as rteBindEitherKW,
   bindReaderK as rteBindReaderK,
@@ -52,12 +52,12 @@ describe('exo8', () => {
     });
   });
 
-  describe('apEitherK[W]', () => {
+  describe('apSEitherK[W]', () => {
     it('should be usable in a happy path do-notation rte pipeline', async () => {
       const pipeline = await pipe(
         rte.Do,
         rte.apS('foo', rte.of(42)),
-        rteApEitherK('bar', either.right(1337)),
+        rteApSEitherK('bar', either.right(1337)),
       )({})();
 
       const expected = await rte.of({ foo: 42, bar: 1337 })({})();
@@ -69,8 +69,8 @@ describe('exo8', () => {
       const pipeline = await pipe(
         rte.Do,
         rte.apS('foo', rte.of<unknown, string, number>(42)),
-        rteApEitherK('bar', either.right(1337)),
-        rteApEitherK('baz', either.left(`Error!`)),
+        rteApSEitherK('bar', either.right(1337)),
+        rteApSEitherK('baz', either.left(`Error!`)),
       )({})();
 
       const expected = await rte.left('Error!')({})();
@@ -82,8 +82,8 @@ describe('exo8', () => {
       const pipeline = await pipe(
         rte.Do,
         rte.apS('foo', rte.of<unknown, string, number>(42)),
-        rteApEitherK('bar', either.right(1337)),
-        rteApEitherKW('baz', either.left(0)),
+        rteApSEitherK('bar', either.right(1337)),
+        rteApSEitherKW('baz', either.left(0)),
       )({})();
 
       const expected = await rte.left(0)({})();
diff --git a/src/exo8/exo8.ts b/src/exo8/exo8.ts
index a8b7048..6385487 100644
--- a/src/exo8/exo8.ts
+++ b/src/exo8/exo8.ts
@@ -12,7 +12,7 @@ import { unimplemented } from '../utils';
 // `Option`, `Either` and the likes such as `map`, `chain` and so on as
 // combinators.
 //
-// The fp-ts library provides a rich collection for such combinators for each
+// The fp-ts library provides a rich collection of such combinators for each
 // type and module but sometimes, you may want to reach for a combinator that
 // doesn't yet exist in the library and it is useful to know how to define
 // your own.
@@ -82,22 +82,22 @@ export const bindEitherK: <N extends string, A, E, B>(
 
 export const bindEitherKW = unimplemented;
 
-// Write the implementations and type definitions of `apEitherK` and
-// `apEitherKW`.
+// Write the implementations and type definitions of `apSEitherK` and
+// `apSEitherKW`.
 //
 // HINT:
 // - remember that "widen" in the case of `Either` means the union of the
 //   possible error types
 
-export const apEitherK = unimplemented;
+export const apSEitherK = unimplemented;
 
-export const apEitherKW = unimplemented;
+export const apSEitherKW = unimplemented;
 
 // Write the implementations and type definitions of `bindReaderK` and
 // `bindReaderKW`.
 //
 // HINT:
-// - remember that "widen" in the case of `Reader` means the interesection of
+// - remember that "widen" in the case of `Reader` means the intersection of
 //   the possible environment types
 
 export const bindReaderK = unimplemented;