Assuming that the box is full of small steel balls, the weight of * * * is 7x30=2 10 g.

266-2 10= 56g less than the actual weight.

And each big bead is more than small beads 1 1-7=4g.

Divide the excess weight by 4g, and the quotient is the number of big beads: 56/4= 14.

The number of beads is 30- 14= 16.