Up and down
Sam got into an elevator. He went down five floors, up six floors, down seven floors, then got out on the second floor. On what floor did he get on?
Age
5 to 7
Challenge level
Problem
Sam got into an elevator.
He went down five floors, up six floors, down seven floors, then got out on the second floor.
On what floor did he get on?
Image
Student Solutions
Anil from Irmak Primary School, Turkey says that "Sam got on the elevator on 8th floor".
This shows how it can be checked out. (Minus means going down, plus means going up).
8 - 5 = 3 (3rd floor)
3 + 6 = 9 (9th floor)
9 - 7 = 2 (2nd floor)
Teachers' Resources
Why do this problem?
This activity
gives pupils the opportunity to see a number of additions and
subtractions taken consecutively and the overall effect.
Possible approach
Introduce the problem to the children orally - you may like to
jot down the information on the board so it can be referred to
easily. Without saying anything else, allow the group
to talk about the problem and how they might solve it.
Share some of these methods before giving time for pairs to
work on a solution together. Encourage them to use
whatever they need to and to record how they want.
In a plenary, you could ask some children to talk about what
they did and what they notice. At this stage, you may
want to introduce the number line as another way to
picture what is happening.
Key questions
What did you do to get your answer?
Why does this way work?
Possible extension
Pupils could suggest similar questions for each other to
solve.
Possible support
It may be appropriate for some children to work with a number
line.