You must use the numeric keypad to type the numbers and not the keyboard. Alt 48 - 57. Keyboard shortcuts for engineering.
Alt 8751 Calculus Symbol.
Enter math expressions You can use keyboard shortcuts to enter the following formats Greek letters symbols and special functions for mathematical expressions whether answering on a computer tablet or smartphone. Stop the mouse over each button to learn its keyboard shortcut. In the Press new shortcut key box type the key combination that you want to use for the symbol or character Eg for symbol used Alt14 and click Assign. The symbols shown are under the Current Keys subset which is already configured with corresponding shortcut keys.