David Albrecht provides some background on what the first generation of computers looked like in his expression of gratitude to the innovations of Commodore International’s founder. See his post, Jack Tramiel 1928-2012.
The VIC-20 had 5K of RAM. Yes, 5K, not 6 megs, Not 1 meg. Not even 512K. Try .005 meg of ram. (That Dell machine I linked to has 1,229 times more RAM than a VIC-20.)
You could buy a cartridge to add 3K or even 8K. But there was only one slot.
The Commodore 64 was so named because the breakthrough was it had that much memory. Yes, a whopping 64K RAM. Yes, that’s .06 megs.