81
After eighty, before
Eighty-one is the number between eighty and eighty-two.
It's nine squared (9 × 9) and the sum of the first nine odd numbers.
In numerology, 81 sometimes carries significance as a "master number." Highway 81 runs north-south through the central United States.
She turned 81 last month.
Rhombus with right angles
- nineEight plus one
- squaredRaised to second power
- rootUnderground absorbing structure
- exponentSuperscript showing power
power · product · equation · integer · digit · sum · multiplication · divisor
Number-matching game of chance
- sudokuLogic grid puzzle
- gridFramework of intersecting lines
- cellBasic unit of life
- squareRhombus with right angles
puzzle · lottery · keno · caller · dauber · card · number · ball
Nine times nine
- tallyRecorded count
- enumerationSequential listing of items
- listingRecorded item in catalog
- reckoningSettlement of accounts
tabulating · calculating · quantifying · itemizing · recording · registering · numeration · inventory
square
Rhombus with right angles
exponent · power · product · equation · integer · digit · sum · multiplication · divisor · factor
bingo
Number-matching game of chance
square · puzzle · lottery · keno · caller · dauber · card · number · ball · cage
eighty-one
Nine times nine
- tallyRecorded count
- enumerationSequential listing of items
- listingRecorded item in catalog
reckoning · tabulating · calculating · quantifying · itemizing · recording · registering · numeration · inventory · cataloging