Thanks Portia, she's definitely completely sound on quantity (if you mean correspondence) but like your son something seems to be going horribly wrong with a partially on the fingers and partially in the head approach to addition and subtraction. I see her waggling her fingers or touching her knuckles and re-doing and re-ding it because she's gotten muddled. I am not sure if it's a problem with her ability to think or a problem with using a completely erroneous method (or weird amalgam of approaches that were never supposed to be smerged).