This is a concrete way of explaining adding integers before introducing students to the actual rules. Students here can see how adding integers works on a number line as well as by using "+" and "-" signs. The first problem is solved for them as an example.
This could also be used for a hand-on activity. The answer key could be blown up and cut out ahead of time. Students then paste each problem, its matching picture, and matching answer in a row on a big colored sheet.
Make sure "Actual Size" is checked in the print dialogue box when printing otherwise, the printer will shrink the worksheet.