Available with Spatial Analyst license.
The Single Output Map Algebra (SOMA) and Multiple Output Map Algebra (MOMA) tools are not available in the Spatial Analyst toolbox. However, existing SOMA and MOMA tools in geoprocessing models and scripts are still supported and will continue to work. If you are using Map Algebra in an existing SOMA or MOMA tools and require additional support, the 9.x Map Algebra documentation can be found online at http://webhelp.esri.com/arcgisdesktop/9.3/index.cfm?TopicName=What_is_Map_Algebra?
When using Map Algebra in ArcGIS 10, it is recommended that you use the 10 version of Map Algebra in the Raster Calculator tool, Python window, or scripting.