The download button opens the iTunes App Store, where you
may continue the download process. You must have iTunes installed with an
active iTunes account in order to download and install the software. This
download may not be available in some countries.
From Catherine Vitti:
Practice solving subtraction problems of one-digit to five-digit numerals. Work column-by-column or by doing the math in your head and selecting from multiple choices.Proper borrowing is enforced in the column-by-column mode. You can display the borrowing in multiple-choice mode as a "helpful hint."Five background color choices, including white-on-black (with no grayscale) for users with mild visual impairment.Ideal for the classroom iPad, where the large numerals allow for demonstrations to a group or for team-based practices.