Tantrums 4&6 year old

[oneheyjude73]

Help my 2 dad's are aged 4 & 6 and I'm at my wits end with their behaviour.
6 year old gets very frustrated and angry at the slightest thing. She grits her teeth and shakes as she's so mad. There isn't anything specific that triggers this off.

4 year old has major paddy's crying and screaming. This morning at school her behaviour left me mortified. I wouldn't carry her reading back (which she always carries herself) and this lead to her crying and shouting. Eventually the head teacher took her into to school (before the bell went) and she tried pulling away and hitting out, the head teacher eventually had to pick her up and carry her in with dd still kicking and screaming. I was so humiliated.
She cries until you tell her it's ok. It's so hard to say its fine when the behaviour is anything but I'm.
On the plus side when one plays up the other tends to be on good behaviour