On a blockchain, participants are represented by strings of numbers and letters known as addresses. (motherboard.vice.com)
The teacher will include songs that will teach numbers and letters in a fun, age appropriate manner. (ourhandsonlearning.com)
If you give them a long link with numbers and letters that make no sense, it is going to be very hard for them to get where you want them to go. (bookpublishingriches.com)