K vs Number Rack, by MLC

K-2 Math Tools A set of math tools to use in K-2 classrooms. No math problems are presented. Use the tools to solve problems from other contexts. The Tools include: marker board, base 10 blocks (1s & 10s), counters in several configuations, 10 frames, 10 bead rows, number line with 10-25 tick marks, 5x5 and 10x10 addition grids, a 100s chart, and a calculator with addition and subtraction only. You may choose to enlarge the size of the 5x5 Grid, the 10x10 Addition Grid, and the Calculator. When selecting a number in the grid 10x10 Addition and 5x5 Addtion charts highlight the number and its addends. The 10 Beads can be set to reverse or alternate the red/white beads. It’s not feasible to use all of the tools at one time, but the tools are draggable so multiple tools may be used at once. For example, the base 10 blocks and the marker board to illustate numbers to 99. The square counters may be shown in sets of 10, 20, or 30. As they are tapped, the center changes to a white square. The number line may be set to begin at any number (including negatives). You may show 10, 12, 15, 20, or 25 tick marks.

Number Rack facilitates the natural development of children’s number sense. The movable, colored beads encourage learners to think in groups of fives and tens, helping them to explore and discover a variety of addition and subtraction strategies. This virtual version of the manipulative is an open-ended educational tool, ideal for elementary classrooms and other learning environments. FEATURES • Display 1 to 10 rows of beads, 10 beads per row. • Hide beads with resizable covers, which allows teachers or learners to model subtraction or difference problems. • Reverse the colors of rows 6 to 10 to distinguish (or not) groupings of 25 beads. • Use the drawing tools to annotate work and show understanding. • Add equations, expressions, and descriptions with the math text and writing tools. • Share work by saving an image or providing a share code to others. Great for creating the initial setup of an activity, then sharing it with students so they can explore it further.