i need to vent dose any one here have this problem ok i have a 7yr old son in home school me and his grandmother split…

i need to vent dose any one here have this problem ok i have a 7yr old son in home school me and his grandmother split the classes he dose great working with his grandmother because she has english social studies i have math and science well he hates math he dose good in it but when he dont want to do it he acts like i beat his butt and i dont i ain't going to lie i do get frustrated and yell sometimes but only when he just sits there and dose absolutely nothing and not try to apply him self he knows the work and how to do it but he is just beginning stubborn and being a brat now what he has been doing is screaming and crying and yelling for grandmothers help like im hurting him and even tells her i hit him when i dont she feeds into it and acts to his defense now he dose this almost every time we learn a new math subject . somtimes he makes me feel like im not a good mom or what did i do for him to act like this. but my son is smart and he just likes to manipulate the situation so he could get out of what it.now it causes me and his grandmother to clash dose any one have any advice?or dose anyone see this Behavior in their child and did you get help? and what kind of help did u get for ur child?