They are in the bottom left hand side of the card(though that may change when the border is changed later in 2014)
If you are attempting to search for a card by the number, Wizards of The Coast provides a tool called the gatherer that can allow you to search and can display the number.
go to wizards of the cost.com
The Magic: The Gathering card search engine offers filters for card type, color, mana cost, and keywords to help players find specific cards quickly and efficiently.
In a game of Magic: The Gathering, if a player fails to find a card with a specific keyword ability when required to do so, they must continue searching until they find a card that meets the criteria. If they are unable to find a card with the specified keyword ability in their deck, they must shuffle their deck and present it to their opponent for a cut.
Magiccards.info is a website where you can find information about Magic: The Gathering cards, including card text, rulings, and prices.
To access the Magic: The Gathering card database for download, you can visit the official Wizards of the Coast website and look for the section dedicated to card databases. From there, you should be able to find a link or option to download the database in a format that suits your needs.
You can find cheap Magic: The Gathering cards for sale at online marketplaces like eBay, TCGplayer, and Card Kingdom, as well as at local game stores and through trading with other players.
In Magic: The Gathering set checklists, you can find a list of all the cards included in a specific card set, including their names and card numbers. This helps players keep track of which cards they have and which ones they still need to collect.
On the Magic: The Gathering spoiler list, you can find information about upcoming cards and sets that have not been officially released yet. This includes card names, abilities, artwork, and other details that players can use to prepare for the new content.
You can find information on purchasing foreign Magic: The Gathering cards from online marketplaces, specialty card shops, and international sellers. Be sure to research the seller's reputation and shipping policies before making a purchase.
You can find affordable Magic: The Gathering cards for sale online on websites like TCGplayer, Card Kingdom, and eBay.
You can find a Magic: The Gathering tournament locator on the official Wizards of the Coast website or by using the Wizards Event Locator tool.
You can find a printable Magic: The Gathering checklist on the official Wizards of the Coast website or on various online resources dedicated to the game.