Numbers-in-Numbers +/-

Recognizes when a number is part of a whole and can keep the part and whole in mind simultaneously; solves Start Unknown ( _ + 4 = 9) problems with counting strategies.


You may see this:

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Other Examples:

  • Asked, "You have some balls, then you get 4 more balls, now, you have 9. How many did you start with?," counts, putting up fingers: "Five, six, seven, eight, nine." Looks at fingers, and says, "Five!"

Help your student become a(n) Numbers-in-Numbers +/-

These activities challenge children to solve all the addition and subtraction problem types they have already learned to solve and the very difficult Join and Separate start unknown problem type ("You had some cars and then you got 5 more, now you had 12. How many did you have to start with?"). Such activities benefit from discussions "parts" and "wholes." Children continue to build and use sophisticated  strategies, including seeing numbers as part of other numbers and using more well-known combinations (e.g., "5 and 5 is 10, so…").

Special Thanks To

Institute of Education Sciences
The research reported here was supported by the Institute of Education Sciences, U.S. Department of Education, through grant numbers R305K050157, R305A120813, R305A110188, and R305A150243. to the University of Denver. The opinions expressed are those of the authors and do not represent views of the Institute or the U.S. Department of Education.