What is claimed is the ornamental design for a calculator, as shown and described.
FIG. 1 is a top perspective view of a calculator, showing the new design;
FIG. 2 is a bottom perspective view thereof;
FIG. 3 is a top plan view thereof;
FIG. 4 is a bottom plan view thereof.
FIG. 5 is a left-side elevational view thereof;
FIG. 6 is a right-side elevational view thereof;
FIG. 7 is a front view thereof; and,
FIG. 8 is a rear view thereof.
The broken lines showing indicia on buttons of the design and logos in FIGS. 1 and 3 are included for the purpose of illustrating the invention in use, and form no part of the claimed design.