Geoboard is exactly what it sounds like. A 25 pin geoboard. Students can explore shapes and geometric concepts. A quick screenshoot saves student work.
Virtual Manipulatives has fraction, decimal, and percentage blocks. Students can compare, find equivalence, and annotate their work.
School Kit Math has 24 math manipulatives and tools. Everything from simple counters to Algebra Tiles means this app is useful for K-8. Tools in SchoolKit Math include: