Laravel sum colum in table

i have two table:

LECTURES
id   name
1 - Lesson 1
2 - Lesson 2
3 - Lesson 3

LECTURESTYPE
id  id_lectures   numb
1 -     1 -        10
2 -     2 -        20
3 -     1 -        30

How can i sum numbs colum for each lesson and take result like : name: Lesson 1 numb: 40 I want to foreach lesson and display sum of numb?

via Chebli Mohamed