Use a number line and add the following integers: (e) (-1) + (-2) + (-3).
On a number line, start move from integer towards left to reach the integer -1. Now move 2 steps to its left to reach the integer -3(adding -2 to -1) and again move 3 steps to left to integer -3(to add -3 to the result) to reach the integer -6.
(-1) + (-2) + (-3) = -6