The rich task advocates (to be fair, of which I am one) are going to slam me for this one; but resorted to a good old fashioned here are 10 (could be any number to fair) equations to solve today. And got the kids working furiously to solve them. Here is how:
As the title suggests the activity is first to solve all 10, but I don't stop when the first has finished. I tell the kids the first to finish will be given number 1, and they have to close their book at that point - no checking, no correcting, nothing. The second person to finish will be given the number 2, the third number 3 and so on until the first 10 people are done (or until a specified time limit). I then reveal the answers and they mark (checked by their peers to ensure they are not cheating if needs be).
What happens next is what catches them - if number 1 gets them all correct they get the reward but if not it passes to number 2. If they haven't answered all correct it passes to number 3 and so on. If none of the first 10 to finish has them all correct then the reward goes to whomever has most correct. Generally it will actually be the 2nd or 3rd person rather than the first that gets the reward but today it turned out to be the eighth person! I like this task occasionally is it encourages kids to balance working hard with working accurately and rewards the person (or with a few adaptations people) that get it right.
We all know (I think at least) there are some times when we just feel kids need to sit down and practice a load of a similar problem and I think this at least provides motivation to approach the task sensibly.