Add hours on a clock (24 hour clock)

Challenge Level: Growing experience

This programming challenge is linked to the following lessons:

Challenge 3.3 for The Modulo operator Unplugged (8 to 10)

Learning outcomes

Students will be able to:

Describe how variables store values and how they are used in your program.
Computer Science: Programming
Explain how to concatenate (join) strings of characters together.
Computer Science: Programming
Identify when to use an if statement to check a set of conditions.
Computer Science: Programming

Requirement:

Write a program that adds hours on a clock; for example, on a 24-hour clock, 11 o'clock plus 3 hours is 14:00. This can be done using the modulo operator.

Testing examples:

Your program should display the outputs shown in this table for the given inputs provided;

Input	Output
11 1	The new time is 12:00.
11 4	The new time is 15:00.
11 12	The new time is 23:00.
22 2	The new time is: 00:00
22 4	The new time is: 2:00
22 22	The new time is: 20:00

Languages

Scratch

What it should look like

Click on the green flag to see the expected output of your program.

View full screen

Recommended blocks

when green flag clicked

set [original time v] to (answer)

set [hours to add v] to (answer)

set [new time v] to (((original time) + (hours to add)) mod (24))

ask [Enter a time:] and wait

ask [Enter the number of hours to add:] and wait

say [The new time is 00:00]

say (join [The new time is ] (join (new time) [:00.]))

if <(new time) = [0]> then
else
end

Hints

Make variables called “original time” and “hours to add” and set their values to the inputs entered by the user. Make a variable called “new time” and set its value to the sum of the “original time” and “hours to add” modulo 24. Display the output as 00:00, If the value of “new time” equal to 0.

Show Scratch solution

Python

Try this challenge out in Plugging it in!

Extra Challenge

Modify your program so the new time is displayed as 24:00, if the value of the “new time” is equal to 0.