Before I introduce addition, I like to show the kids that there are "math partners" or sums in the equation. I explain that two numbers are put together to create a new number or the whole.
The first page you can do with linking cubes. Students pick linking cubes from a ziplock. I put two colors in the ziplock bag. If the number is 5, they pick 5 cubes and look at what two colors they picked. If they pick 2 and 3, they color in the picture and write a corresponding equation.
On the second and fourth page, students draw a picture of math partners and write a matching equation. To add subitizing, students can roll a dice for the two math partners.
The third page, students can create their own equations. I give the students a number of counters. They separate the counters with a popsicle stick. This divides the whole into two parts. For students who struggle, I give them less counters. For advance students I give them more counters for bigger equations.
Feel free to use these worksheets however you want with the math manipulatives you have in your classroom! Enjoy!