In a 50g (1.75 oz) bobbin there are about 90 m (98 yd) so for quantities to knit plan on:
700g = 14 balls for men size M
600g = 12 balls for women size M
400g = 8 balls for children size 10 yrs.
Machine wash at 30°C (86°F) with detergent for wools without fabric softener.