Queue
There are 25 students queuing in a straight line.
Julia is the 19th from the front, Urvisha is the 14th from the back.
How many students are there between Julia and Urvisha?
Try using cubes to represent the students.
How many students are in front of Urvisha?
Chiu from Arcadia High School and Harry from St James' School sent in well explained solutions. Harry describes how he solved the problem:
The answer is 6 students. I numbered each of the students, 1 for the front and 25 for the back. Julia was obviously no. 19. I counted from 25 back 14 places (starting with 25 so the solution would be right). I found that Urvisha was no. 12. Then I counted the numbers between 12 and 19 and got 6.
Chiu drew a diagram to help answer the problem:
From the picture above, there are 25 students queuing in a straight line. Since Julia is the 19th from the front, Urvisha is the 14th from the back, which means there are 6 students between Julia and Urvisha.
Queue
There are 25 students queuing in a straight line.
Julia is the 19th from the front, Urvisha is the 14th from the back.
How many students are there between Julia and Urvisha?
Why do this problem?
Possible approach
Having introduced the problem, give pairs time to discuss how they could go about solving it.Share some suggestions and then invite pupils to have a go, using whatever materials they would like.
You could use children in the class to act out the solution as a final check.
Key questions
Could you use some equipment to help you? Or could you draw a picture?How many students are in front of Urvisha?