zero
1234567890 + 4563217890 = 5797785780
456789 * 1234567890 = 5.63937032 × 1014
1,000,460 with remainder 250.
It has one base and one face.
1234567890
1234567890
1234567890
1234567890
Just 1.
1234567890
1234567890
1234567890 billon
112345678890 1234567809 1234567890 12345678990 123467890 1234567890 1234567890
2469135780
zero
Oh, what a happy little question! With the digits 1-9 and 0, you have 10 options for each digit in a 4-digit number. So, you can form 10 x 10 x 10 x 10 = 10,000 different 4-digit numbers. Isn't that just delightful? Just imagine all the beautiful combinations you can create!