Hi Mary,
Technically, with a 640 you can apply to any school you like. I have a lot of experience helping people with low GMAT scores or low GPAs (usually not both) get into top schools.
Some stories of hope: I got into HBS and HKS (Harvard Kennedy School) as well as waitlisted at Stanford with a 620 GMAT. Two seasons ago, a client of mine (Asian-American male in his 30s) got into Ross with a 620 GMAT, and before that, a client of mine (Mexican-American male in his 30s) got into Kellogg with a 640 GMAT.
When your GMAT is low, it's imperative that you have outstanding essays that clearly communicate why you want to go to the school (personal, professional, and academic reasons), what you bring to the school in and outside of the classroom, why NOW is the time for you to go to b-school, and all the reasons why your low GMAT score (or for others, a low GPA) is not indicative of your ability to handle the quantitative rigor of the business school classroom.
Rather than pigeon-holing yourself into a group of schools based on your score, use it as a reference point. Apply to 2-3 reach schools where your score is WAY out of range, 3 scores where your score is closer to their target range, and 2 schools where you have a very high chance of being admitted.
It sounds like you could use some encouragement and guidance. I invite you to visit my website to see if I might be a good match for you.
Best of luck with your process!
Warm regards,
Kaneisha
https://theartofapplying.com
Harvard Business School MBA 2010, Harvard Kennedy School MPA 2010
Founder, The Art of Applying
Admissions Consulting for MBA, MPP, Joint Degrees, and Fellowships
https://theartofapplying.com
Want free advice that actually works? Sign up for my weekly MBA, MPP, and JD newsletter here:
https://theartofapplying.com/newsletter/
My clients have earned over $3.1 million in fellowships from Harvard and other top MBA, MPP, and JD programs since 2010.