In Numbers for iOS 3.1 and later, double-tap on a cell or tap to start editing. When you start entering data, Numbers automatically recognizes what you put in a cell and formats it appropriately. For example, if you enter in "$100", Numbers automatically formats the cell for currency. If you want to choose a different format for the cell, tap the cell you want to edit, then tap . Tap if you want to change the format's settings.
When you edit a cell that is formatted as a number, currency, or percentage, Numbers automatically switches to a numeric keypad. If you want to use a numeric keypad and it doesn't automatically switch, tap .
If you're on an iPad1, you can use the formula keyboard to enter numbers and symbols quickly. If a keyboard isn't already visible, tap , or tap to begin editing a formula. To quickly enter a number or symbol, drag downward on its key and then lift your finger. You can also enter a symbol by tapping the shortcut buttons above the keyboard.
1This feature might not be available on all iPad models.