Learning Resources Interlocking Base Ten Starter Set Units are made of durable, washable plastic for years of hands-on activities|Help students understand abstract base ten concepts; including place value, estimation, operations and fractions|141 pieces include: 100 units, 30 rods, 10 flats, 1 cube, and 96-page Base Ten Activity Book|Starter set perfect for use with 3-4 students|Ideal for ages 6+ Engage students in concrete demonstrations of place value and base ten concepts with this interlocking Base Ten Starter Set. Units are made of durable, washable plastic for years of hands-on activities. 141 pieces in all.