Thank you, but that's basically wrong. Even by their own convoluted base 10 measurement method where a "GB" = 10^9 bytes rather than 2^30, the Sandisk "200GB" is only 196GB. They are falsely advertising the capacity.
It says on the packaging 200GB*
The * has the disclaimer that 1GB = 1,000,000,000 bytes. Actual user storage less.
The card has a total usable capacity of 196,798,840,832 bytes. That's not 200GB by their definition. A 128GB Sandisk USB 3.0 flash drive with the same disclaimer has 128,027,983,872 bytes. A 64GB Sandisk USB 3.0 flash drive has 64,018,710,528 bytes. A 64GB Sandisk SDXC card has 63,831,015,424 bytes. A 32GB Sandisk SDXC card has 31,902,400,512 bytes.
So, other Sandisk products basically comply with their redefinition of a GB, but not the "200GB" microSDXC card. As a percentage is much more short than any of the others on bytes. If they were consistent it would be about 500MB short of 200GB, not 3200MB short.
Not wrong, but maybe misunderstood. You seem to have the basic idea, regardless of the deeper explanation -- The manufacturers gently mislead consumers.