During International Education Week, children from different countries compare their school life. 1) In your culture. Compare your and Jack's school bags, school subjects and classrooms.

Составим пропорцию:
Пусть 1200 -это 100% 
1)1200:100=12 деталей в 1 %
2)12*30=360 деталей
ответ:360 деталей изготовил ученик 

1200- 100% => 
1200/100=12 деталей
12 деталей=1%
12*30=360 
ответ: 360 деталей