Unit 1

Giving exact instructions

Tell a robot how to reach the star, one careful step at a time, and find out why "go over there" never works.

1. Read

   Telling a robot where to go

   Mina hid a sweet in the garden. Her little brother Arun wants to find it.

   "Go over there!" says Mina.

   Arun walks to the water tap. "No! More that way!" says Mina. Arun walks into the wall.

   Poor Arun. "Over there" does not tell him enough. How far? Which way? Where should he turn?

   A robot is even more careful than Arun. A robot does exactly what you tell it, and nothing else. So if you want a robot to do something, your instructions must be exact.

   Steps and algorithms

   A list of exact steps is called an algorithm. Each step is one small thing to do. A good algorithm is so exact that anyone who follows it gets the same result.

   Robot Ravi's three commands

   Robot Ravi lives on a grid of squares. He understands only three commands:

   Command	What Ravi does
   Forward	Moves one square the way he is facing.
   Turn left	Stays in the same square and turns to face left.
   Turn right	Stays in the same square and turns to face right.

   

   Writing a route

   Ravi starts in the bottom-left square, facing up. The star is two squares up and two squares to the right. Here is a route that gets him there. Watch the picture: each step lights up as Ravi does it.

   

   Example.

   1. Forward. Ravi moves up one square.
   2. Forward. Ravi moves up one more square.
   3. Turn right. Ravi is still in the same square. Now he faces right.
   4. Forward. One square to the right.
   5. Forward. One more square to the right. He is on the star!

   Five exact steps. Anyone can follow them and finish on the star.

   Two tricky things

   Turning does not move you. A turn changes which way Ravi faces. It does not use up a square. Only Forward moves him.

   Left and right are Ravi's left and right. If Ravi faces down the page, then Turn left makes him face the right side of the page! A good trick: stand up, face the way Ravi faces, and turn your own body.

   Try it: Use the robot route builder. Write a route, press Run, and watch the robot do exactly what you wrote.

   Following someone else's route

   When you follow a route, do just what each step says. Do not skip steps. Do not do what you think the writer meant. Point at each step with your finger and move the robot one step at a time. That is how a computer works too.

   For the grown-up helping

   Let your child be the robot first, with real steps on the floor, before drawing routes on paper. Use the same three words every time (forward, turn left, turn right). Mixing up left and right is very normal at this age: have your child stand and face the way the robot faces. If a route fails, do not fix it for them. Ask "What did the robot do? What did you want it to do?" and let them find the step.

2. Lab

   Robot route builder

   Build routes of Forward, Turn left and Turn right to get the robot to the star. Then follow someone else's route in your head and check where the robot stops.

   Your goals

   • Write routes that take the robot to the star in three missions, one with rocks in the way.
   • Follow a route written by someone else and say where the robot will stop.

   🔒 The interactive lab opens once you register. Register to do this.

3. Activity

   Be the robot

   Make a grid on the floor. Your child writes a route for you, and you follow it exactly like a robot. Then you swap. About 20 minutes.

   You'll need

   • Chalk (outside) or 16 sheets of paper to lay on the floor in a 4 by 4 square
   • A small toy or cup for the "treasure"
   • Three small cards or pieces of paper marked Forward, Turn left, Turn right
   • Paper and a pencil

   Steps

   1. Lay out a 4 by 4 grid. Put the treasure on one square and mark a start square. Say "The robot stands on the start square, facing the treasure's side of the room."
   2. Show the three commands. Forward moves one square the way you face. Turn left and Turn right turn on the spot.
   3. Your child lays the cards in a row to make a route from the start to the treasure. Do not help yet.
   4. Be the robot. Follow the cards one at a time, doing exactly what each card says, even if it is wrong. Say "Beep" at each step.
   5. If the robot does not reach the treasure, ask "What did the robot do? Which step should change?" Let your child change the cards and try again.
   6. Swap. You lay out a route (make it 5 or 6 cards). Your child is the robot and follows it exactly.
   7. Finish by asking "Why can't I just say go to the treasure?"

   Safety

   • Clear the floor of toys and furniture to trip on, and keep well away from stairs.
   • Use chalk only outdoors on paving, or paper squares indoors. No tape on delicate floors.

   🔒 Keeping a log of the activity is for registered learners. Register to do this.

4. Quick check

   Exact instructions check

   Seven questions about robot routes. The robot's commands are Forward, Turn left and Turn right.

   1. 1.The robot faces up. Which route takes it to the star?

      
      • Forward, Forward, Turn right, Forward, Forward
      • Forward, Forward, Turn right, Forward
      • Forward, Forward, Turn left, Forward, Forward
      • Turn right, Forward, Forward

      Choose one

   2. 2.The robot follows this route: Forward, Forward, Turn right, Forward. Which square does it stop in?

      
      • A
      • B
      • C

      Choose one

   3. 3.The robot faces the right side of the picture. The star is right above it. What should the robot do first to reach the star?

      
      • Forward
      • Turn left
      • Turn right

      Choose one

   4. 4.Mina tells a robot "Go over there." The robot does not move. Why?

      • The instruction does not say how far to go or which way to turn.
      • Robots are too slow to understand.
      • The robot must be broken.

      Choose one

   5. 5.A route is: Forward, Turn right, Forward, Forward, Turn left, Forward. How many squares does the robot move in all?

      Answer with a number

   6. 6.Match each command to what it does.

      • Forward
      • Turn left
      • Turn right

      Match each to: Stays in the same square and faces left · Stays in the same square and faces right · Moves one square the way the robot faces

   7. 7.These steps for washing hands are mixed up. Put them in an order that works.

      • Dry your hands
      • Turn on the tap
      • Rinse the soap off
      • Rub soap on your hands
      • Wet your hands

      Put these in order

   🔒 Answering and checking are for registered learners. Register to do this.

5. Quick check

   New puzzles

   Routes and instructions in new places. Use what you know.

   1. 1.A rock is in the way. Which route takes the robot to the star without bumping into the rock?

      
      • Turn right, Forward, Forward
      • Forward, Turn right, Forward, Forward, Turn right, Forward
      • Forward, Turn right, Forward, Turn right, Forward
      • Forward, Turn right, Forward, Forward, Turn left, Forward

      Choose one

   2. 2.A robot faces up. It does Turn right, then Turn right again. Which way does it face now?

      • Up
      • Right
      • Down
      • Left

      Choose one

   3. 3.Kabir is writing steps for a robot. Which step is exact enough?

      • Go over there
      • Move forward 3 squares, then turn left
      • Walk a little way and turn when it feels right

      Choose one

   4. 4.A robot faces up. The star is 2 squares straight ahead and then 1 square to the right. What is the fewest number of steps that gets the robot to the star?

      Answer with a number

   🔒 Answering and checking are for registered learners. Register to do this.

6. Activity

   Tell it back

   Your child explains, in their own words, why a robot needs exact instructions. Three minutes.

   Steps

   1. Ask "Mina said go over there and Arun walked into a wall. What was wrong with her instruction?" Let your child answer without hints.
   2. Ask "What would you say to a robot instead?" Your child can show with the Forward, Turn left and Turn right cards, or by using their hands.
   3. Ask "Why does the robot do just what the steps say?" and "What is a list of exact steps called?" Write down what your child says in their own words.

   🔒 Keeping a log of the activity is for registered learners. Register to do this.