Common Core Unknown Number with Flower Petal

One of the Common Core math standards for first grade is determining the unknown number. It is a standard that is somewhat tricky for my first graders. Obviously those students with strong number sense get it, but it has been more difficult for the others.

Determining the Unknown Number with Flower Petals is a set of worksheets that I created to help students begin to understand what they are looking for; what it means when there is a missing number; and how to figure out what number goes in the missing number spot. It has been very helpful to my students. The set includes three addition and three subtraction sheets, which isn’t a lot, but the student are able to carry this strategy over to other similar worksheets or problems I assign for their math journals.

The way the Unknown Number with Flower Petals worksheets work is that students draw flower petals (circles) around the unknown number box as they are counting up for addition or back for subtraction. Once they have the flower petals drawn they count the petals and then write that number in the missing number box. Students do need to be encouraged to draw neatly or they have difficulty being able to see/count the petals. I also like having them put a mark on each petal while they are counting in order to help them count more accurately.

As I’ve mentioned already, this strategy could be used with any unknown number worksheet, but I have made my Determining the Unknown Number with Flower Petals set available at my teacher’s store. Please feel free to check it out, or to view my other products if you are interested.

 Determining the Unknown Numbers with Flower Petals