# TI-BASIC:Number Subset

**Routine Summary**

Returns a subset of a number.

**Inputs**

*A* - the number to get the subset from
*B* - the starting position of the subset
*C* - the length of the subset

**Outputs**

*Ans* - the subset of the number

**Variables Used**

A, B, C, Ans

**Calculator Compatibility**

TI-83/84/+/SE
**Author**

Weregoose*URL:* United TI
**Download**

:10^(2-B+int(log(A :int((A-int(A/Ans)Ans)/Ans10^(C

With our number stored in A, and the staring position and length of the subset stored in B and C respectively, we get the subset of the number by first subtracting the number divided by 10 to the power of 2-B+int(log(A (which is used to get how many digits are in the number), and then dividing that result by multiplying 10 to the power of 2-B+int(log(A and 10 to the power of C (which is the length of the subset).

A simple example should help you understand this routine. Say you input the number 123, with a starting position of 2 and a length of 2, it will return a result of 23. You can also use negative and decimal numbers with the routine, and it will still work correctly: a number of 13579.02468 with a starting position of 4 and length 4 will return 7902.

This routine is comparable to the Sub( command that works with Strings.