Anchors of 5 and 10 are important ideas for children developing relationships between numbers--specifically, as the name implies, 5 and 10. As children we used the most readily available counter for counting up and down--our fingers. As many of us grew older we internalized the relationships and generalized it for larger numbers. We began to see numbers as some relationship to 5 or 10.
The number 8, for example, is 3 more than 5, or 2 less than 10. The number 32 is simply three 10s and 2 more. A subtraction problem 32-17 might be solved using an anchor of 10. 3 more than 17 is 20, 10 more is 30 and 2 more is 32; 3+10+2 is 15. The process is incremental and children develop it through experience and practice. Some children internalize the process with little to no explanation, while others do not.
Some children don't make those connections as easily and need explicit instruction to develop the concepts. 5-and 10-frames are a great resource in developing 5 and 10 anchors. A 5-frame is a simple 1x5 array and a 10-frame is a 2x5 array. It can be drawn on paper, found as a blackline master in textbooks or online, created on word processing software, etc. I always introduce 5-frames first and move to 10-frames after the student has shown mastery. For some it may be a week or two; for others it may be a day or two.
This lesson is an overview of 5-and 10-anchors, 5-and 10-frames, and a demo of introducing and using a 5-frame.
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