Original: The first group, about three-quarters of the total, went to the gas chambers of Auschwitz-Birkenau within a few hours; they included almost all children, women with children, all the elderly, and all those who appeared on brief and superficial inspection by an SS doctor not to be fully fit.
Simplified: This 66% generally included all children, all women, all elderly persons, and others whom SS officers thought not fully fit to do work.