If you are looking for an easy mental math warm up activity that can be used with any grade level, will get brains working, is open-ended, will appeal to all abilities, and doesn't require photocopying, then you may like to try this super simple mental math warm up activity that became part of my regular routine during math time with all of my classes.
First, instruct students to open up to an empty page in their math workbooks OR give them a blank piece of paper. Next, give them a number - now this can vary depending on the grade level. For second grade you may choose a simple single or double digit number, but for sixth grade you might choose a much larger number or even go with a fraction or decimal number to make it more challenging. In the example below I have chosen the number 25. |

Allocate four 'guidelines' you want students to follow when making the number. For example:

1 - Use operations to make 25 (add, subtract, multiply or divide)

2 - Include decimals or fractions (or make it a challenger box appropriate for your grade level)

3 - Draw it

4 - Make word problems

Now I expect at least one thing done for every box from all of my students, but the point of the activity is to push them to make 25 in as many ways as possible in a set time frame (I give my students 10 minutes). Once the ten minutes is up, I invite students to share one of their ideas with the rest of the class. I encourage and praise ways that seem super creative and stand out from the flock.

All students I have done this with start to love it once they get the hang of it. In fact, it almost always seemed to give several students a sense of competitiveness as they tried to get the most problems down on their page and come up with the most creative ways. You will be amazed how some students may grow in their way of approaching the task every time it is done.

After a few times with the guidelines, I then no longer have to tell my students to do the four sections. Instead, I give them complete free open range and challenge them to come up with the most interesting ways to make the number! I get them to simply set up a page in their workbook as in the image below, give the number, set the timer and off they go. I always state that I expect to see the page looking full just to nudge on the few that need it. When it comes to reflection time (we only spend a few minutes on this), I encourage students to share their most creative idea to make the number. The encouragement and sharing (I found) helped those few students who were stuck on only ever doing the simple stuff like 99 + 1, 98 + 2, to move on to trying to think of other ways to do it.

PLUS . . . if you ever find you need a few more minutes to prepare for an upcoming lesson this also is a great yet meaningful emergency activity to do while you get your stuff sorted out.