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Numbers coding challenges
Practise numbers with 16 coding challenges, from easy to hard. Every challenge runs in your browser with instant tests, an AI review of your code and community solutions to compare.
Easy · 13 Medium · 2 Hard · 1
Skills you'll practise: ConditionsDivisibilityModuloBig numbersBit manipulationBoolean logicComparisonsCounting rangesDigit DPDigit extractionDigit reversalDigit strings
- Python · C++ · C#
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- 226
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All challenges
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Easy
Prime Number Check
Decide whether a number is prime.
You'll learn
DivisibilityLoop optimization
No solutions yet
Hard
Count Numbers With Distinct Neighbors
Count range values whose adjacent decimal digits are never equal.
You'll learn
Digit DPCounting ranges
No solutions yet
Easy
Doubling Grains on a Chessboard
Calculate a square’s grain count and the total on all 64 squares.
You'll learn
Powers of twoBig numbers
No solutions yet
Easy
Sum Even Fibonacci Terms
Add the even Fibonacci terms that do not exceed a limit.
You'll learn
Sequence generationFiltering
No solutions yet
Medium
Subtract Digits to Reach Zero
Use as few digit subtractions as possible to reach zero.
You'll learn
Minimum steps DPGreedy choice
No solutions yet
Easy
Collatz Sequence
Follow the halve-or-triple-and-add-one rule until reaching 1.
You'll learn
While loopsStep counting
No solutions yet
Easy
Power of Two
Check whether a number is a power of two.
You'll learn
Bit manipulationDivision
No solutions yet
Easy
Least Common Multiple
Find the smallest positive number divisible by both values.
You'll learn
GCD and LCMNumber theory
No solutions yet
Easy
Palindrome Number
Check whether a number reads the same backwards.
You'll learn
Digit reversalComparisons
No solutions yet
Easy
Armstrong Number
Check whether a number equals the sum of its digits raised to the digit count.
You'll learn
Digit extractionPowers
No solutions yet
Easy
Greatest Common Divisor
Find the largest number that divides both values.
You'll learn
Euclid's algorithmModulo
No solutions yet
Easy
Leap Year
Check whether a year follows the Gregorian leap-year rule.
You'll learn
Boolean logicConditions
No solutions yet
Medium
Largest Adjacent-Digit Product
Take every contiguous window of span digits and multiply its digits.
You'll learn
Fixed-size windowsDigit strings
No solutions yet
Easy
Sum of Multiples
Add values below a limit divisible by any supplied factor.
You'll learn
LoopsDivisibility
No solutions yet
Easy
Odd, Even, or Neither
Classify a number by whether it is an odd integer, an even integer, or neither.
You'll learn
ModuloConditions
No solutions yet
Easy
Fizz Buzz
Build a sequence using divisibility by 3 and 5.
You'll learn
ConditionsDivisibility
No solutions yet
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