Sequences and Algorithms

An algorithm is a list of steps in the right order. To make a jam sandwich, which step comes FIRST?

• AEat the sandwich
• BSpread the jam on the bread
• CGet two slices of bread✓
• DPut the two slices together

Answer: You need the bread out before you can do anything else, so getting the bread is the first step.

Here is a morning algorithm: 1) Wake up, 2) Get dressed, 3) Eat breakfast, 4) Go to school. What is step 3?

• AGo to school
• BEat breakfast✓
• CGet dressed
• DWake up

Answer: Counting along the list, the third step is eating breakfast.

To plant a seed you: dig a hole, put the seed in, cover it with soil, then water it. What do you do just AFTER putting the seed in?

• ADig a hole
• BEat the seed
• CWater it
• DCover it with soil✓

Answer: After the seed is in the hole, the next step is covering it with soil before watering.

Why does the ORDER of steps in an algorithm matter?

• ADoing steps in the wrong order can give the wrong result✓
• BYou can do all the steps at the same time and it still works
• CGetting the order right only matters when you are cooking
• DThe order of the steps never changes what happens

Answer: If you pour the milk before you get the bowl out, it goes all over the table. The order of the steps has to make sense.

A robot's steps to leave a room are: 1) Stand up, 2) Walk to door, 3) Walk through the doorway. Which step is missing if the robot cannot get out?

• ASit back down
• BWalk to door
• COpen door✓
• DStand up

Answer: If the robot forgets to open the door, it will bump into it, so opening the door is the needed step.

Which of these is the BEST description of an algorithm?

• AA set of steps to follow to do a task✓
• BA type of computer screen you can draw on
• CA funny picture you print out and colour in
• DA single button you press to start a game

Answer: An algorithm is just a clear list of steps you follow to finish a task.

To brush your teeth: 1) Put toothpaste on brush, 2) Brush teeth, 3) Rinse mouth. What comes LAST?

• AOpen the toothpaste
• BPut toothpaste on brush
• CBrush teeth
• DRinse mouth✓

Answer: The last step in the list is rinsing your mouth after brushing.

Tom wrote steps to make tea but mixed them up: A) Pour hot water, B) Get a cup, C) Add a teabag. What is the correct order?

• AC, A, B
• BB, C, A✓
• CA, B, C
• DA, C, B

Answer: You get the cup first, add the teabag, then pour the water, so the order is B, C, A.