Numbers and fingers are both called digits.
The tens digit.
tenth thousand
The value of a digit in a number is called its place value.
In any two-digit multiplication sum, for example, 3 x 2 = 6, the first digit is called the multiplier, the second digit is called a multiplicand, and the third digit, the answer, is the product.
digit
The tens digit.
The first digit of the hand is called the thumb.
It is called a 28-digit number!
tenth thousand
The value of a digit in a number is called its place value.
In any two-digit multiplication sum, for example, 3 x 2 = 6, the first digit is called the multiplier, the second digit is called a multiplicand, and the third digit, the answer, is the product.
digit
Bit
Just that - a 26-digit number. There is no special name for that.
A 400-digit number is typically referred to as a "400-digit number." In mathematics, numbers are categorized by their number of digits, such as single-digit numbers, double-digit numbers, triple-digit numbers, and so on. Therefore, a number with 400 digits would simply be called a "400-digit number."
Rounding to the first digit is simply called rounding. This will make the number equal to the same as what the number truly is.
Bit