85 (number) facts for kids

Eighty-five is a number that comes right after eighty-four and just before eighty-six. It is an odd number, which means you can't divide it evenly by two.

You can divide 85 by a few numbers without having any leftover. These numbers are 1, 5, 17, and 85 itself. These are called its divisors.

What Makes 85 Special?

The number 85 has some interesting features in mathematics and other areas. It's a composite number because it has more divisors than just 1 and itself.

Math Properties of 85

• Odd Number: As mentioned, 85 is an odd number. When you try to divide 85 by 2, you get 42 with a remainder of 1.
• Composite Number: A composite number is a positive integer that can be formed by multiplying two smaller positive integers. For 85, you can multiply 5 by 17 to get 85.
• Divisors: The numbers that divide 85 perfectly are 1, 5, 17, and 85.
• Sum of Squares: 85 can be written as the sum of two squares in two different ways!
  • It's 2 squared plus 9 squared (2² + 9² = 4 + 81 = 85).
  • It's also 6 squared plus 7 squared (6² + 7² = 36 + 49 = 85).
• Figurate Number: 85 is a centered square number. Imagine dots arranged in a square shape, with one dot in the very center. If you add layers of squares around it, the total number of dots can be a centered square number. 85 is the 6th centered square number.

85 in Everyday Life

The number 85 appears in various places:

• Speed Limits: In some countries, 85 miles per hour (or kilometers per hour) might be a speed limit on certain highways.
• Chemistry: The element Astatine has the atomic number 85. Astatine is a very rare and radioactive element.
• Sports: In many sports, players wear jerseys with numbers. You might see a player wearing the number 85.
• Years: 85 can refer to a year, like 1985 or 2085. Many important events happened in the year 1985 around the world.

See also

In Spanish: Ochenta y cinco para niños