[Currency Exchange]: Reworded task explanations

exercises/concept/currency-exchange/.docs/instructions.md

@@ -7,12 +7,11 @@ Your friend Chandler plans to visit exotic countries all around the world. Sadly
 Create the `exchange_money()` function, taking 2 parameters:
 
 1. `budget` : The amount of money you are planning to exchange.
-2. `exchange_rate` : Unit value of the foreign currency.
+2. `exchange_rate` : The amount of domestic currency that equals one unit of foreign currency.
 
 This function should return the value of the exchanged currency.
 
-**Note:** If your currency is USD and you want to exchange USD for EUR with an exchange rate of `1.20`, then `1.20 USD == 1 EUR`.
-
+**Note:** If there are converting USD to EUR, and there are `1.20 USD` in `1.00 EUR`, the exchange rate is `1.20`.
 ```python
 >>> exchange_money(127.5, 1.2)
 106.25
@@ -39,7 +38,7 @@ Create the `get_value_of_bills()` function, taking 2 parameters:
 1. `denomination` : The value of a single bill.
 2. `number_of_bills` : Amount of bills you received.
 
-This function should return the total value of the given *bills*.
+This exchanging booth only deals in cash. The total you receive must be divisible by the value of one bill, which can leave behind a reminder. This function should return the total value of the given *bills*.
 
 ```python
 >>> get_value_of_bills(5, 128)
@@ -50,8 +49,8 @@ This function should return the total value of the given *bills*.
 
 Create the `get_number_of_bills()` function, taking `budget` and `denomination`.
 
-This function should return the *number of bills* that you can get using the *budget*.
-**Note: ** You can only receive _whole bills_, not fractions of bills,  so remember to divide accordingly.
+This function should return the *number of bills* that you can get using the *budget*. In other words, how many bills of the denomination's value fit into the total budget
+**Note: ** You can only receive _whole bills_, not fractions of bills,  so remember to divide accordingly. You are rounding down to the nearest whole number.
 ```python
 >>> get_number_of_bills(127.5, 5)
 25
@@ -61,8 +60,8 @@ This function should return the *number of bills* that you can get using the *bu
 
 Create the `exchangeable_value()` function, taking `budget`, `exchange_rate`, `spread`, and `denomination`.
 
-Parameter `spread` is the *percentage taken* as an exchange fee.
-If `1.00 EUR == 1.20 USD` and the *spread* is `10`, the actual exchange will be: `1.00 EUR == 1.32 USD`.
+Parameter `spread` is the *percentage taken* as an exchange fee, written as an integer. It needs to be converted to decimal by dividing it by 100. 
+If `1.00 EUR == 1.20 USD` and the *spread* is `10`, the actual exchange rate will be: `1.00 EUR == 1.32 USD` because 10% of 1.20 is 0.12, and this additional fee is added to the exchange.
 
 This function should return the maximum value of the new currency after calculating the *exchange rate* plus the *spread*.
 Remember that the currency *denomination* is a whole number, and cannot be sub-divided.
@@ -80,7 +79,7 @@ Remember that the currency *denomination* is a whole number, and cannot be sub-d
 
 Create the `non_exchangeable_value()` function, taking `budget`, `exchange_rate`, `spread`, and `denomination`.
 
-This function should return the value that is *not* exchangeable due to the *denomination* of the bills.
+This function should return the value that is *not* exchangeable due to the *denomination* of the bills, by subtracting your value after exchange from the theoretical value. The theoretical value assumes bills can be subdivided, therefore ignoring denomination, but does take into account spread.
 
 **Note:** Returned value should be `int` type.