25 OCT 2017 by ideonexus

## Blockchains

Ownership on the Bitcoin blockchain is determined by a pair of cryptographic keys. The first, called the public key, resides in the blockchain for anyone to see. The second is called the private key, and its owner keeps it safe from view. The two keys have a special mathematical relationship that makes them useful for signing digital messages. Here’s how that happens: Helmut takes a message, combines it with his private key, does some calculations, and ends up with a long number. Anyone who...03 APR 2015 by ideonexus

## The Give-N Task for Assessing Child Number Knowledge

Children learn very early (often as young as 2 years old) to recite the number-word list in order (Fuson, 1988). But at the beginning, the words are merely placeholders—children recite the list without knowing what the individual number words mean. Over time, children fill in the words with meaning, one at a time and in order (Carey, 2009; Sarnecka & Lee, 2009). The child’s progress on this front is called their number-knower level, or just knower level. A child who does not yet know ...There is also an excel spreadsheet referenced inth