diff --git a/640.md b/640.md
index 5682381..3f69e81 100644
--- a/640.md
+++ b/640.md
@@ -93,6 +93,48 @@ m1 = dw.getMotor(1)
 
 #### Motor driving
 
+There are two main commands that you can give a motor - to move in a direction and to stop. We'll start with the main command to stop the motor
+
+``` python
+m1.off()
+```
+
+We can also stop the motor by using the second command and passing a speed of 0
+
+``` python
+m1.setMotorSpeed(0)
+```
+
+The **setMotorSpeed* command allows you to specify the speed of each motor - there are two different speed ranges the first goes from *-255* to *255*, the second from *1000* to *2000*. 
+
+If you are familiar with radio control vehicles and ESC motors then you will recognise the second range.
+
+For now we'll concentrate on the first range.
+
+To get your motor going forwards at full speed you should set its speed at 255
+
+``` python
+m1.setMotorSpeed(255)
+```
+
+To get your motor going backwards at full speed you should set its speed to -255
+
+``` python
+m1.setMotorSpeed(-255)
+```
+
+The numbers from 0 to the maximum in each direction will drive the motor at a slower speed, so for half speed forwards we'd use
+
+``` python
+m1.setMotorSpeed(125)
+```
+
+And for a slow speed backwards we can use
+
+``` python
+m1.setMotorSpeed(-50)
+```
+
 #### Select a Servo
 
 #### Servo control