About this worksheet: This worksheet is meant to allow the teacher to grade for correct answers quickly and accurately without grading every single problem by hand. You should tell the students that the dots will not form a picture like they are used to. You can tell them that if they do it correctly then a hexagon can be found somewhere on the page (it is not necessary to tell them though), but it may not be made with the dots on the paper. The hexagon is for you to help identify whether or not students did the bulk of the worksheet correctly. Note that the hexagon is formed by making straight line segments from point to point, so the students do need to use a straightedge when connecting the dots.
Determine the unknown whole number in an addition or subtraction equation relating three whole numbers. For example, determine the unknown number that makes the equation true in each of the equations 8 + ? = 11, 5 = _ - 3, 6 + 6 = _.