My child had a eye exam because of her right eye crossing inward toward nose right eye is 20/100-2 her left eye is 20/40-2 does this mean her eye sight is bad ?

The difference between the strength of the eyes is a problem. The brain likes a clear image & the two images should overlap and be clear. If one is blurry, the brain can shut off the weak eye & without its input, cross eyes can occur. Glasses may help correct this if you do it soon enough. Otherwise it could need surgery or have vision loss.