Explain to your class that positive numbers don't normally carry the "+" symbol because people most often work with positive numbers; so if there is no symbol in front of the number, it is positive. Negative numbers always have the "-" symbol in front of them. Ensure students understand the difference between positive and negative numbers by holding up an index card with a number printed on it. Ask students to identify if the number is positive or negative. Help students recognized the opposites; for example, +20 is the opposite of -20. Point out to students that the only difference between the numbers is the symbol in front of it.
Display a labeled number line on the blackboard and explain that the negative numbers are located on the left side of the zero and the positive numbers are located on the right side of the zero. Show students how to move along the number line by using both positive and negative numbers. Check for comprehension with a fun activity where students move a manipulative --- such as an eraser--- across their own number line. Have students start their manipulative on the number zero, then move the object back and forth according to the teacher's instructions. For example, if the object started on the number zero, moved three positive spaces, two negative spaces, three positive spaces and negative five spaces the object would land on the -1 space at the end of the exercise.
While most people are only familiar with the positive side of temperatures, during the harsh winter months temperatures can reach into the negative figures. Help students understand differences in extreme temperatures by showing them a visual of a thermometer set to a summer temperature, such as 90 degrees, and then showing them a thermometer indicating the temperature during a winter blizzard, particularly with the "wind chill factor." Assign students to draw pictures of appropriate temperatures for different times of the year, or color in a thermometer to a particular temperature. Ensure that students label the thermometer with the correct temperature.
Help students strengthen their integer skills by working with written problems that add and subtract integers. Provide a small number line for each student to refer to when first working with number lines. Using the visual cue aids in comprehension and helps ensure students understand how to work the breaks. Assign students written integer problems such as: +23 + -30 =? Consider assigning a word story to the problem, such as buying items and making money to help students understand the concept better.