Matilda and her sisters each got 20 chocolate bars / 5 people = <<20/5=4>>4 chocolate bars/person
They each gave 4/person / 2 = <<4/2=2>>2 chocolate bars/person to their father.
Their father received 2 chocolate bars/person x 5 people = <<2*5=10>>10 chocolate bars
Their father had 10 chocolate bars - 3 chocolate bars - 2 chocolate bars = <<10-3-2=5>>5 chocolate bars left.
#### 5