These write-on, wipe-off cards are ideal to help students solve operations, ratio, and a variety of other problems. Features a single line on one side, and two number lines on reverse. Measures 4" x 20" each. Each pack includes 10 number lines. Sold as 3 packs for a total of 30 number lines.. Ideal help students solve equations. Single line on one side, and two number lines on reverse. Durable blank write-on/wipe-off number lines. 4" x 20" each. 10 per pack, sold as 3 packs, 30 number lines total. 5-11 years. Grade K-5