Cut apart the number searches so each student gets one-fourth of the page.
Choose a number you want students to find addends for. Write this number in the blank center box. Students can find addends vertically, horizontally or diagonally. (I usually keep the middle number between 6 and 20.)
You can give each student a different number search (to discourage copying) OR you can give each student the same number search to encourage collaboration (or competition!)
You can also give different students different numbers in the blank middle box to meet their developmental level.
Blank sheet, examples of student work and directions included.