Hundredious (The 100 Cells Puzzle Game) (Free - Extra content via in-app billing)
Will you defeat Hundredious, the 100 Cells puzzle ?
The rules are simple. Chose one cell to start at, skit two cells straight our one diagonally, and try to get as close as possible to 100 !

VLSM IP Subnets calculator - Cisco IOS Command Reference (Free - Premium Version via in-app billing)
Calculates for you (or checks what you calculated) Variable Length Subnet Mask, which allows you to divide your network into sub networks without address covering (both IPv4 & IPv6 (IPv6 is not released yet on iOS)).
Also regroups every useful command to configure Cisco devices such as routers and switches.

Wearable Calculator for Apple Watch (Free - Extra content via in-app billing)
Calculating has never been that easy !
Calculator app for iPhone and Apple Watch