Bitcoin wallet balance doesn't add up to what my addresses have I have had a bitcoin core wallet on windows for a long time. For most of this time I have been inactive. My client has gone out of sync and  my wallet sat on my computer as well as a backup on a usb stick. Recently I decided to get back into crypto, so I re-synced my client to the blockchain. Dropped my old wallet back into the client. It went through the rescan process, and to my surprise I had more bitcoin than my addressees say they have on blockchain.info. 

I even decided to dump all my private keys from my core wallet, and import them into an electrum wallet to see what it would yeild. And upon doing so, my electrum wallet has less bitcoin than my core wallet.  

How is this possible, considering both wallets are built off the same private keys?
I struggled with this too. There are many other addresses created when you send/receive funds from bitcoin.

Don't just run dumpprivkey with your receiving BTC addresses; run dumpwallet to a file instead and import all keys (left-hand side of the dump file) prior to 1 Aug 2014 to Electrum.cash wallet.