The rand() Command

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Command Summary

Generates a random number.

Command Syntax

rand() or rand(n)

Menu Location

• Press 2nd MATH to enter the MATH popup menu.
• Press 7 to enter the Probability submenu.
• Press 4 to paste rand(.

Calculator Compatibility

This command works on all calculators.

Token Size

2 bytes

The rand() command generates a random number. It can be used in one of two ways:

• rand() gives a random real number between 0 and 1.
• rand(n) gives a random integer between 1 and n.

By adding or multiplying appropriately, you can change these bounds. For example, 10rand() gives a random real number between 0 and 10, and rand(9)-5 gives a random number between -4 and 4.

L'Ecuyer's algorithm is used by TI calculators to generate pseudorandom numbers.

:RandSeed 0
:rand()
           .943597402492
:rand()
           .908318860975
:rand(10)
           2

Advanced Uses

Using the RandSeed command makes the random numbers entirely predictable: after setting the random seed to some value, the same random numbers will be returned every time.

Error Conditions

260 - Domain error happens when the maximum number is 10¹⁴ or greater.

Related Commands

• RandSeed
• randNorm()
• randMat()
• randPoly()