This might be one of my new favorite tasks.  It might be the experience of seeing the attendant turn the adding machine around once my son and I had mentally calculated the total or it might just be because I got to play (and win) Coin Dozer (my absolute favorite game)!  Please tell me what you think by commenting on how you will or have used it in your classroom!

When we go to the arcade, my son doesn’t like to wait to turn in his tickets so we always end up with several separate sheets of ticket totals by the end of our visit.

The task below could be used for CCSS 4.NBT.B.4 and MLS 4.NBT.A.5.

I love this problem because act 3 allows the student to engage in MP3 “construct viable arguments and critique the reasoning of others” as well as MP6 “attend to precision.”

Act 1:

What do you notice?  What do you wonder?

How many tickets does he have? Write a too high estimate, write a too low estimate.

Act 2:

Act 3:

The attendant came up with this total.  Is he correct or incorrect?

Would you be happy or unhappy with this total?  Why?

(Side note, when I asked him if I could take a picture of it for a math lesson he said “I rounded up for you.”  I think there might be some great talk around this too:)

For example:

What does he mean he rounded up?  What was he rounding to?  The nearest 10, the nearest 100 or something else?

Update!

Here is the actual total with calculator strokes.  I think this is important for students to see once they finish their calculations and discuss.