A calculator or computer can not only be a useful tool to save time and check arithmetic, but also to do calculations, draw pictures, and make explorations which would not be manageable otherwise.  However, you should not become overly dependent on your calculator or computer.  There are basic skills in calculus which we believe you should be able to carry out "by hand."  It is very unlikely that you will be allowed a calculator on any exam in this class, so you should start to cultivate an independence from these tools with respect to your understanding of the material; only with understanding comes the power to wield technology responsibly and efficiently!