tens

Tens refers to the decimal place value in the base-10 number system and to the group of numbers built from tens. In base-10, each digit in a number has a weight that is a power of ten, with the ones place being 10^0, the tens place 10^1, the hundreds place 10^2, and so on. The tens place is the second digit from the right and carries a weight of 10.

The digit in the tens place can range from 0 to 9. The value contributed by that digit is the digit multiplied by 10. For example, in the two-digit number 47, the tens digit is 4, representing 40, while the ones digit is 7, representing 7. In three-digit numbers such as 305, the tens digit is 0, contributing 0 tens toward the total. The digits to the left form higher place values (hundreds, thousands), and the digits to the right form lower place values (ones).

Tens can also refer to the set of integers that are multiples of ten, such as 10, 20, 30, 40, and so on. These numbers have a unit digit of 0 and share the common property of being 10 times some integer.

In arithmetic, the tens place is central to many operations. When adding numbers, carries may occur from the ones into the tens if the sum of ones is ten or more. Multiplication by 10 shifts each digit one place to the left, placing a zero in the ones place and increasing the tens place accordingly. Rounding to the nearest ten is based on the value in the ones place.

Understanding tens is a fundamental aspect of place-value concepts, contributing to literacy in arithmetic, estimation, and mental math.