An
algorithm
a day
Ye a r 1 0 D i g i t a l Te c h n o l o g i e s
Bream Bay College
What is an algorithm?
An algorithm is a
step-by-step procedure that
allows a computer to solve a
problem.
Contents
1. Comparing Numbers (Scratch Solution)
2. Days of the Week (Scratch Solution)
3. Roll the dice! (Scratch Solution)
4. Teach an old dog new tricks… (Scratch Solution)
5. Adding up a list (Scratch Solution)
6.Taxi! Taxi! (Scratch Solution) [Test Data]
7. Bear with me (Scratch Solution) [Test Data]
8. Isosceles (Scratch Solution) [Test Data]
9.
10.
1. Comparing Numbers
5 is bigger
than 3
Write an algorithm which:
a. Asks the user to input two numbers.
b. Outputs the larger of the two numbers along with
a suitable message.
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1. Comparing Numbers—Scratch
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2. Days of the Week
If Monday = 1, Tuesday = 2 etc,
write an algorithm which:
a. Asks the user to enter a number.
b. Outputs the day that the number represents.
c. Validates the number so that an error message displays
if the number is not a valid weekday number.
d. Makes the program loop.
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2. Days of the Week—Scratch
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3. Roll the dice!
A program has been
written to obtain three
random virtual dice rolls.
a. Rewrite this program so that it uses a loop.
b.Create your own dice sprite in Scratch, with six
costumes. Change the costume to match each dice
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roll.
3. Roll the dice!—Scratch
Pa r t a
Pa r t b
• This needs about three blocks.
• A solution will be posted in due course.
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4. Teach an old dog new tricks…
A dog that is 5 years old is equivalent to a 42 year
old human. Write a program that converts the age of
a dog to the equivalent age of a human.
a. Ask for the age of the dog in years.
b. If the age is 2 or less, the human equivalent is 12
times the age.
c. If the age is more than 2, the human equivalent is
24 for the first 2 years, plus 6 for
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every additional year.
4. Teach an old dog…—Scratch
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5. Adding up a list
a. In Scratch, make a list called numbers.
b. Add each of the following to your numbers list:
2, 5, 3, 6, 2, 3, 6, 4.
c.
Write a program which adds up the numbers in
the list and displays the result.
Use a loop for doing this.
d. Calculate the average (mean) number.
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5. Adding up a list—Scratch
Explain the purpose
of each block in this
program.
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6. Taxi! Taxi!
A taxi firm charges $5 for the first kilometre and $2
for every km after that. If there are 5 or more
passengers, an extra 50% is added to the price.
Create an app in Scratch which:
a. Asks for the number of passengers (1 to 12);
b.Asks for the distance (1km to 60km);
c. Calculates the price of the journey;
d.Outputs the price on the screen.
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6. Taxi! Taxi!—Test Data
Number of passengers
Distance (km)
Cost
1
5
$13
4
12
$27
5
15
$49.50
12
8
$28.50
14
14
Invalid Number
3
65
Invalid Distance
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6. Taxi! Taxi!—Scratch
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7. Bear with me
In a factory, the wage earned by a worker is either $5 for
every teddy bear they have made or $20 for every hour they have
worked, whichever is higher.
Make a Scratch app which:
a.
Asks for the number of teddy bears made (1 to 1,000) and the
number of hours worked (1 to 50);
b.
Calculates the wages for the number of teddy bears made;
c.
Calculates the wages for the number of hours worked;
d.
Outputs the larger of the two results.
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7. Bear with me—Test Data
Teddy Bears
Hours
Per Teddy
Per Hour
Output
28
6
$140
$120
$140
52
15
$260
$300
$300
200
40
$1,000
$800
$1,000
72
22
$360
$440
$440
1001
50
Invalid Teddies
800
51
Invalid Hours
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7. Bear with me—Scratch
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8. Isosceles
An isosceles triangle is one which has at least two equal length sides.
Create a Scratch program which:
a. Asks the user to enter the lengths of a triangle;
b.Works out if the triangle is isosceles;
c. Outputs a message stating whether the triangle is isosceles or not.
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8. Isosceles—Test Data
Side 1
Side 2
Side 3
Output
3
4
5
Not Isosceles
7
7
4
Isosceles
12
5
12
Isosceles
14
8
8
Isosceles
5
12
13
Not isosceles
9
9
9
Isosceles
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8. Isosceles—Scratch
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