New user of micro SD card

I am new to tablets and micro SD cards.  I recently bought a new tablet, and a new SanDisk 32GB micro SD card.  I inserted the new micro SD card into the tablet, however, the tablet shows the SD card is inserted, but, indicates storage space is running out, with 31.24 GB of storage space.  I am unable to download any new apps, because of the lack of storage.  Does the micro SD card need to be formatted?  There is no setting on the tablet to format the micro SD card.  Can anyone offer any advice?

Computers define the capacity as 1:1024

1GB=1024MB

But the manufacturer define the capacity as 1:1000

1GB=1000MB

Some capacity is not available for data storage.

If new apps cannot be downloaded to the card, you may download them to the tablet. 

And if you want to format your card, just put it into a card reader and connect it to a computer, then format it.