Minor revertion to its original sentence structure albeit keeping Richard's ;calculation'

ch04.asciidoc

@@ -74,7 +74,7 @@ When spending bitcoins, the current bitcoin owner presents their public key and
 
 [TIP]
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-In most implementations, the private and public keys are stored together as a _key pair_ for convenience. However, the public key can be calculated from the private key, so it's possible to storing only the private key.
+In most implementations, the private and public keys are stored together as a _key pair_ for convenience. However, the public key can be calculated from the private key, so storing only the private key is also possible.
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 ==== Private and Public Keys