While researching a topic on the internet, I stumbled across this
really great site that is perfect for warm-ups or bell ringers or when
you want to work on developing their ability to explain choices. Its
called Would You Rather?

This
activity has pictures with an open ended question but which ever one, A
or B, you choose you have to explain your answer. Depending on the
problem, you may be required to justify your answer with mathematics.

The
problems usually use a real world scenario such as pizza, chips,
apples, or even sports teams. Some of the problems include a link so
you can add activities in or at least read up on the topic so you know
more about it. If it deals with sports, I usually have to look things
up because I love Australian Rules but that is not a sport my students
know about so I have to use theirs. The author has 9 pages of these
lovely thought provoking questions.

Another site I found that could also be used during bell ringers or warm ups is something called Visual Patterns.
This site has 220 patterns that show the first three iterations in
the pattern and then asks you to find the number of objects if the
pattern is repeated to level 43. They also ask for the equation but
they only provide the answers for the pattern to level 43.

These
visual patterns are wonderful because they do offer some great thought
but I would add that students need to show how they got their answer by
showing their work in some manner. This activity requires higher level
thinking because you have to figure out the mathematical pattern or
equation in order to find the answer to the question.

The final site if from Estimation 180
which is a site designed to help develop number sense. There are about
220 pictures, each with a question requiring students to estimate the
height of someone or something, estimate the number of things, etc. All
questions that help fine tune their number sense. I looked at one that
showed one cheetos cheese ball on a cookie sheet and asked students to
estimate how many will it take to fill the tray. He does not give one
answer, he actually provides a video answer for the question.

In
addition to these short activities, Estimation 180 also has lesson
plans for grades 4 to 8 with a variety of topics such as expressions and
equations, geometry etc. I like that the lesson plans are actually
more of a here is what I did, this is what my students responded, and
this is where I got the material from.

I love these types of activity because these are a way of developing math
literacy in the classroom. I plan to use these as openers in my
classroom so students have something to work on while I take roll and do
the usual housekeeping during the first 5 min of class. I'd like to thank US News and World Report for these websites.