In a ball of 100g (3.5 oz) there are about 75 m (82 yd) so allow:
1000g = 10 skeins for men size M
800g = 8 skeins for women size M
500g = 5 skeins for children 10 yrs
Machine wash at 30°C (86°F) with detergent for wool without fabric softener.