150g = 7x5 squares = 35 squares of the blanket

so, about 23 squares per ball.

I want it to be another 2 wide and 4 long, so in total it will be 7 wide by 11 long, 7x11 = 77. 77 - 35 = 42 so I need another 2 balls. Maybe 3 if I edge it.