A good source to improve Quant

I began preparing for GMAT by October '17. Back then i was struggling hard in Quant. My average score was hovering around 30-35 for nearly two months.

A friend told me about GMAT tests and I started taking gmat club tests twice in a week. My scores began improving gradually.
I didn't enroll for any other course either online or offline. For Quants I did only general question from GMAT club and took test regularly.
I took my GMAT on April 4th and I scored 48 in quants.
It was a pretty improvement for me from 30 to 48.
Though I'm preparing to retake since my verbal needs further improvement,still i would prefer these tests.

These tests will let you know where you need more efforts to put in. Number properties questions will eventually boost your scores. I found many questions which added significant parts to my preparation.
These questions are bit harder than what you will face on the D day. Practising these will make you feel more confident.