diff --git a/Sprint-1/2-mandatory-errors/0.js b/Sprint-1/2-mandatory-errors/0.js
index cf6c5039f..65ad3030d 100644
--- a/Sprint-1/2-mandatory-errors/0.js
+++ b/Sprint-1/2-mandatory-errors/0.js
@@ -1,2 +1,2 @@
-This is just an instruction for the first activity - but it is just for human consumption
-We don't want the computer to run these 2 lines - how can we solve this problem?
\ No newline at end of file
+//This is just an instruction for the first activity - but it is just for human consumption
+//We don't want the computer to run these 2 lines - how can we solve this problem?
\ No newline at end of file
diff --git a/Sprint-1/2-mandatory-errors/1.js b/Sprint-1/2-mandatory-errors/1.js
index 7a43cbea7..d660966b7 100644
--- a/Sprint-1/2-mandatory-errors/1.js
+++ b/Sprint-1/2-mandatory-errors/1.js
@@ -1,4 +1,5 @@
 // trying to create an age variable and then reassign the value by 1
+// I changed for let
 
-const age = 33;
+let age = 33;
 age = age + 1;
diff --git a/Sprint-1/2-mandatory-errors/2.js b/Sprint-1/2-mandatory-errors/2.js
index e09b89831..6d4dc4ae3 100644
--- a/Sprint-1/2-mandatory-errors/2.js
+++ b/Sprint-1/2-mandatory-errors/2.js
@@ -1,5 +1,7 @@
 // Currently trying to print the string "I was born in Bolton" but it isn't working...
 // what's the error ?
+// I have ti change the order
 
-console.log(`I was born in ${cityOfBirth}`);
 const cityOfBirth = "Bolton";
+console.log(`I was born in ${cityOfBirth}`);
+
diff --git a/Sprint-1/2-mandatory-errors/3.js b/Sprint-1/2-mandatory-errors/3.js
index ec101884d..e95738ad1 100644
--- a/Sprint-1/2-mandatory-errors/3.js
+++ b/Sprint-1/2-mandatory-errors/3.js
@@ -1,4 +1,4 @@
-const cardNumber = 4533787178994213;
+/*const cardNumber = 4533787178994213;
 const last4Digits = cardNumber.slice(-4);
 
 // The last4Digits variable should store the last 4 digits of cardNumber
@@ -7,3 +7,9 @@ const last4Digits = cardNumber.slice(-4);
 // Then run the code and see what error it gives.
 // Consider: Why does it give this error? Is this what I predicted? If not, what's different?
 // Then try updating the expression last4Digits is assigned to, in order to get the correct value
+/*Answer> The code will not works because slice is strigs and array and
+cardNumber is number */
+const cardNumber = 4533787178994213;
+const last4Digits = cardNumber.slice(-4);
+
+
diff --git a/Sprint-1/2-mandatory-errors/4.js b/Sprint-1/2-mandatory-errors/4.js
index 21dad8c5d..2ce09132e 100644
--- a/Sprint-1/2-mandatory-errors/4.js
+++ b/Sprint-1/2-mandatory-errors/4.js
@@ -1,2 +1,7 @@
-const 12HourClockTime = "20:53";
-const 24hourClockTime = "08:53";
\ No newline at end of file
+/*const 12HourClockTime = "20:53";
+const 24hourClockTime = "08:53";
+*/
+
+//Answer:
+const Hour12ClockTime = "20:53";
+const hour24ClockTime = "08:53";
\ No newline at end of file
diff --git a/Sprint-1/3-mandatory-interpret/1-percentage-change.js b/Sprint-1/3-mandatory-interpret/1-percentage-change.js
index e24ecb8e1..bdae7723d 100644
--- a/Sprint-1/3-mandatory-interpret/1-percentage-change.js
+++ b/Sprint-1/3-mandatory-interpret/1-percentage-change.js
@@ -1,4 +1,4 @@
-let carPrice = "10,000";
+/*let carPrice = "10,000";
 let priceAfterOneYear = "8,543";
 
 carPrice = Number(carPrice.replaceAll(",", ""));
@@ -12,11 +12,29 @@ console.log(`The percentage change is ${percentageChange}`);
 // Read the code and then answer the questions below
 
 // a) How many function calls are there in this file? Write down all the lines where a function call is made
+/* carPrice.replaceAll(",", "")  línea 4
+Number(carPrice.replaceAll(",", ""))  línea 4
+priceAfterOneYear.replaceAll("," "")  línea 5
+Number(priceAfterOneYear.replaceAll("," ""))  línea 5
+console.log(...)  línea 9
+Total> 5 calls
 
 // b) Run the code and identify the line where the error is coming from - why is this error occurring? How can you fix this problem?
 
+is missing coma
+console.log(...)  in line 9
+
 // c) Identify all the lines that are variable reassignment statements
+carPrice = Number(carPrice.replaceAll(",", "")); in line 4
+priceAfterOneYear = Number(priceAfterOneYear.replaceAll(",", "")); in line 5
 
 // d) Identify all the lines that are variable declarations
 
+let carPrice = "10,000";  línea 1
+let priceAfterOneYear = "8,543";  línea 2
+const priceDifference = carPrice - priceAfterOneYear;  línea 6
+const percentageChange = (priceDifference / carPrice) * 100;  línea 7
+
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+become a price that is string with comas fixed ready to run and show the %
+*/
diff --git a/Sprint-1/3-mandatory-interpret/2-time-format.js b/Sprint-1/3-mandatory-interpret/2-time-format.js
index 47d239558..c58262195 100644
--- a/Sprint-1/3-mandatory-interpret/2-time-format.js
+++ b/Sprint-1/3-mandatory-interpret/2-time-format.js
@@ -11,15 +11,37 @@ console.log(result);
 
 // For the piece of code above, read the code and then answer the following questions
 
+
 // a) How many variable declarations are there in this program?
+/* 6 variables 
+movieLength
+remainingSeconds
+totalMinutes
+remainingMinutes
+totalHours
+result
 
 // b) How many function calls are there?
+1 call
+console.log(result)
 
 // c) Using documentation, explain what the expression movieLength % 60 represents
 // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators
 
+% is the modulo operator.
+It returns the remainder of dividing movieLength by 60.
+In this case: it calculates how many seconds are left over after counting the full minutes.
+
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
 
+First, subtract the remaining seconds to get only the whole seconds in minutes. Then, divide by 60 to convert seconds to whole minutes.
+
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
 
+The result contains a string in the format: hours:minutes:seconds
+movieDurationString
+
+
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+
+It works for positive numbers of seconds. */
diff --git a/Sprint-1/3-mandatory-interpret/3-to-pounds.js b/Sprint-1/3-mandatory-interpret/3-to-pounds.js
index 60c9ace69..010dcad89 100644
--- a/Sprint-1/3-mandatory-interpret/3-to-pounds.js
+++ b/Sprint-1/3-mandatory-interpret/3-to-pounds.js
@@ -1,4 +1,4 @@
-const penceString = "399p";
+/*const penceString = "399p";
 
 const penceStringWithoutTrailingP = penceString.substring(
   0,
@@ -25,3 +25,20 @@ console.log(`£${pounds}.${pence}`);
 
 // To begin, we can start with
 // 1. const penceString = "399p": initialises a string variable with the value "399p"
+/* 2. const penceStringWithoutTrailingP = penceString.substring(0, penceString.length - 1);
+Use .substring(start, end) to remove the last character (p) from the string.
+penceString.length - 1  index of the last character excluding p
+3. const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
+Use .padStart(targetLength, "0") to ensure the chain has at least 3
+4. `const pounds = paddedPenceNumberString.substring(0, paddedPenceNumberString.length - 2);`
+
+`Extracts the digits from the pounds.` `paddedPenceNumberString.length - 2` → leaves the last two digits for the pence.`
+5. const pence = paddedPenceNumberString.substring(paddedPenceNumberString.length - 2).padEnd(2, "0");
+
+.substring(start)  takes the last two characters, which represent the penny
+
+.padEnd(2, "0")  ensures there are always two digits, padding with 0 if necessary
+6. console.log(£${pounds}.${pence});
+
+Builds a string in the standard price format: £pounds.pence
+