HeyJaredDave'sMathNotations
Dedicated to Math Teachers Discussions of the what, the why and the how of math instruction from Birth to Infinity
- Indexed issues, last 90 days
- 5
- Latest publication
- Sep 28, 2026
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- Earliest in this view
- Sep 24, 2026
Latest issues
“Like a circle in a spiral, like a wheel within a wheel” (opens the original)
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Consider all chords in a circle, whose length equals the radius. The set of midpoints of these chords forms a circle, whose area is what percent of the area of the original circle?Dave'sMathNotations is a reader-supported publication. To receive new posts and support my work, consider becoming a free or paid subscriber.<input class="button primary" type="submit" v
What Is the Largest Power of 2 Hidden in 100!? (opens the original)
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Here is a question that begins with elementary arithmetic but leads somewhere much deeper:The symbol 4! is read “4 factorial” and means:4! = 4 · 3 · 2 · 11. What is the largest power of 2 that is a factor of 4!?Find the answer in any way you choose.You may have multiplied first:Dave'sMathNotations is a reader-supported publication. To receive new posts and support
2026² = ? Visualizing the Distributive Property! (opens the original)
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<img alt="" class="sizing-normal" height="1199" src="https://substackcdn.com/image/fetch/$s_!zo7q!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F07337df3-8b64-4794-9f20-ad678ffd2b67_1312x1199.p
From 9 × 9 to 99,999 × 9 - Using Powers of 10 and Distributive Property (opens the original)
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Using 10 to Multiply by 9 9･9 = (10 - 1) ･ 9 = 10 ･ 9 - 1 ･ 9 = 90 - 9 = 81(a) Could I have replaced either 9 by 10-1? Dave'sMathNotations is a reader-supported publication. To receive new posts and support my work, consider becoming a free or paid subscriber.<div class="f
Anything special about 79 and 97? (opens the original)
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Gr 5-8Write a few observations about the numbers 79 and 97. E.g.,, they’re both odd, but I know you can do better than that!Dave'sMathNotations is a reader-supported publication. To receive new posts and support my work, consider becoming a free or paid subscriber.<div class="fake-input-
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