Homework can be found on Google Classroom. Just go to the "Classwork" tab (not the stream) and click on Homework on the left menu.

4A Homework Link - https://classroom.google.com/w/MzIwMTU3MjAyOTEw/tc/MzIwODMzNDc3MjA0

4B Homework Link - https://classroom.google.com/w/MzIwMTU3MjAyOTgy/tc/MzIwODMzNDc3MTI0