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99 CHART—MENTAL MATH STRATEGIES

Grades: K‒3

Students use a 99 chart (a chart numbered from 0 to 99) to model mental math strategies for addition and subtraction. Four directional controls allow students to navigate through the chart by adding or subtracting 1 or 10. By connecting these movements through the chart with their mathematical meaning, students develop a deeper understanding of addition and subtraction.

OBJECTIVES 
  • Students will use an interactive 99 chart to model addition and subtraction.
  • Students will develop and refine their mental math strategies for addition and subtraction.
COMMON CORE CONNECTIONS 
Mathematical Practices

(1) Make sense of problems and persevere in solving them; (2) Reason abstractly and quantitatively; (3) Construct viable arguments and critique the reasoning of others; (4) Model with mathematics; (5) Use appropriate tools strategically; (6) Attend to precision; (7) Look for and make use of structure.

Content Standards

1.NBT; 2.NBT5, 6, 9

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This activity is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License: http://creativecommons.org/licenses/by-nc-sa/3.0/. If you adapt and/or share this activity, you must attribute it to "KCP Technologies, a McGraw-Hill Education Company." You may distribute it only non-commercially under the same or similar license.


This material is based upon work supported by the National Science Foundation under KCP Technologies Award ID 0918733, with grant period September 1, 2009 through August 31, 2013. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.
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