This book about the fourth grade math problems in primary school is specially arranged for everyone, hoping to help everyone!

First, oral calculation.

840÷40= 180×30= 520÷4= 150×4=

350÷7= 720÷30= 36×20= 900÷5=

450÷90= 18×3= 702÷3= 27×3=

2. How many can I put in brackets?

35×( )