Subtraction Concentrated app for iPhone and iPad

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.

There are no ads, no in-app purchase, no interruptions, distracting sounds or music. This was designed for an instructional setting.