Summary: From the beginning, I took this calculator everywhere. It is likely the most powerful, durable, and resilient machine of its kind. The interface is great, and it can handle even the most complex computations. But that is only the tip of the iceberg. I grew to truly love the little machine, using it several times a day. It was truly the companion of my travels. One fateful day, after about a year of good use, I spilled energy drink all over it.