numbers washed off the temp knob

While visiting in Minnesota I was cleaning my Mothers GE range, I cleaned the numbers right off the temperature knob. Panicking I called my husband in Florida, gave him the number that was sort of visable on the back of the knob. The numbers were not the same but I said the knob is black and any knob with the oven temperatures numbers should fit. He ordered it, they said three days. Sure enough three days it arrived. Now me not telling my Mother what I had done went to my daughters house for a few days. I got a call from my sister, who checks on Mother, laughing her head off. She said Mother had gotten the package and told the delivery lady that she hadn't ordered anything that it wasn't hers. The delivery lady said the name and address was hers. She then helped Mother who has arthritic fingers open the package and proceeded to the stove where she took off the old knob and put on the new one. Mother was thrilled