In just twenty minutes a day you can achieve mathematics success. These drills and work sheets will help your children with number counting, subtraction, and math on an number line. SPI Math workbooks are committed to education and mastery. Great for public school supplementation, or homeschooling. Don't let math drills go by the wayside during the summer months. Spending just a few precious moments everyday will keep your kids sharp and ahead of the pack. This is one in a series of first grade math books. Be sure to check out the other ones.