Mike Jacobs
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mikejacobs.bsky.social
Mike Jacobs
@mikejacobs.bsky.social
460 followers 45 following 570 posts
Math teacher in Ontario/Mountaineer/Munroist/Exiled Yorkshireman/Dad to two great kids.
Creator of Yohaku Puzzle https://www.yohaku.ca/
Author of Onwards and Upwards. https://tinyurl.com/OnwardsUpwardsHills .
#RunEveryDay
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mikejacobs.bsky.social
Happy New Year everyone! Here's a special #yohaku to celebrate. Fill in cells with 16 different factors of 2600 to get totals shown in each row/column AND shaded cells contain square numbers.
Use 16 different factors of 2600 in a 4 by 4 grid. The numbers in the top row add to 388. The numbers in the second row add to 221. The numbers in the third row add to 101. The numbers in the bottom row add to 73. The numbers in the left column add to 36. The numbers in the second column add to 177. The numbers in the third column add to 199. The numbers in the right column add to 371. The central four cells contain square numbers.
January 1, 2026 at 2:49 PM
mikejacobs.bsky.social
Much as I love doing the Jumble each day, I think that there is a little math error in today's puzzle.
A Jumble puzzle that gives the answer 'In their prime' to the clue 'Numbers 1, 2, 3, 5 and 7 will never show signs of age and always be…'
December 26, 2025 at 2:36 PM
mikejacobs.bsky.social
Here's a special Christmas #yohaku! Fill in cells with 25 different factors of 840 to get totals shown in each row/column AND shaded cells contain triangle numbers.
Use 25 different factors of 840 in a 5 by 5 grid. The numbers in the top row add to 90. The numbers in the second row add to 17. The numbers in the third row add to 555. The numbers in the fourth row add to 206. The numbers in the bottom row add to 184. The numbers in the left column add to 35. The numbers in the second column add to 86. The numbers in the third column add to 621. The numbers in the fourth column add to 118. The numbers in the right column add to 192. The eight cells surrounding the central square contain triangle numbers.
December 25, 2025 at 4:19 AM
mikejacobs.bsky.social
Slàinte! Wishing everyone a happy winter solstice!
Grianstad an Gheimridh sona dhuibh!
A beer bottle of vintage ale next to a glass of beer on a kitchen counter.
December 22, 2025 at 2:54 AM
mikejacobs.bsky.social
Here's a #yohaku to take you into the weekend. Fill in cells with 16 different factors of 612 to get totals shown in each row/column AND shaded cells contain square numbers. #mathsky #iTeachMath
Use 16 different factors of 612 in a 4 by 4 grid. The numbers in the top row add to 937. The numbers in the second row add to 37. The numbers in the third row add to 258. The numbers in the bottom row add to 292. The numbers in the left column add to 516. The numbers in the second column add to 91. The numbers in the third column add to 15. The numbers in the right column add to 902. The central four cells contain square numbers.
December 19, 2025 at 12:11 PM
mikejacobs.bsky.social
Try this shady #yohaku. Fill in cells with 9 different integers to get products shown in each row/column AND sum of 4 shaded cells is -1. #mathsky #iTeachMath
Use 9 different integers in a 3 by 3 grid. The numbers in the top row multiply to -180. The numbers in the middle row multiply to -16. The numbers in the bottom row multiply to -627. The numbers in the left column multiply to 360. The numbers in the middle column multiply to 88. The numbers in the right column multiply to -57. The sum of the integers in the 2 by 2 square at the top left of the grid is -1.
December 18, 2025 at 12:15 PM
mikejacobs.bsky.social
Start your day with this #yohaku. Fill in cells with 9 different factors of 216 to get totals shown in each row/column. #mathsky #iTeachMath
Use 9 different factors of 216 in a 3 by 3 grid. The numbers in the top row add to 33. The numbers in the middle row add to 47. The numbers in the bottom row add to 168. The numbers in the left column add to 171. The numbers in the middle column add to 66. The numbers in the right column add to 11.
December 17, 2025 at 11:51 AM
mikejacobs.bsky.social
Start your day with this #yohaku. Fill in cells with 9 different whole numbers to get products shown in each row/column. More free puzzles and books/ebooks for all ages can be found at yohaku.ca
Use 9 different whole numbers in a 3 by 3 grid. The numbers in the top row multiply to 84. The numbers in the middle row multiply to 64. The numbers in the bottom row multiply to 420. The numbers in the left column multiply to 392. The numbers in the middle column multiply to 24. The numbers in the right column multiply to 240.
December 16, 2025 at 11:45 AM
mikejacobs.bsky.social
Start your week with this #yohaku. Fill in cells with 9 different factors of 216 to get totals shown in each row/column. #mathsky #iTeachMath
Use 9 different factors of 216 in a 3 by 3 grid. The numbers in the top row add to 33. The numbers in the middle row add to 47. The numbers in the bottom row add to 168. The numbers in the left column add to 171. The numbers in the middle column add to 66. The numbers in the right column add to 11.
December 15, 2025 at 12:07 PM
mikejacobs.bsky.social
Looking for Christmas stocking stuffers? Why not try one of my yohaku puzzle books?
Five colourful Christmas stockings each with a yohaku puzzle book sticking out of the top.
December 13, 2025 at 7:37 PM
mikejacobs.bsky.social
A student told me that their calculator was giving the wrong answer. 'Look! I know that 32 divided by 2 is 16. Why does it say 19?'
Can you see what is happening?
December 13, 2025 at 12:12 AM
mikejacobs.bsky.social
Here's a #yohaku to take you into the weekend. Fill in cells with 16 different factors of 828 to get totals shown in each row/column AND shaded cells contain square numbers. #mathsky #iTeachMath
Use 16 different factors of 828 in a 4 by 4 grid. The numbers in the top row add to 713. The numbers in the second row add to 232. The numbers in the third row add to 106. The numbers in the bottom row add to 29. The numbers in the left column add to 107. The numbers in the second column add to 145. The numbers in the third column add to 143. The numbers in the right column add to 685. The central four cells contain square numbers.
December 12, 2025 at 11:58 AM
mikejacobs.bsky.social
Try this shady #yohaku. Fill in cells with 9 different integers to get products shown in each row/column AND sum of 4 shaded cells is -7. #mathsky #iTeachMath
Use 9 different integers in a 3 by 3 grid. The numbers in the top row multiply to 72. The numbers in the middle row multiply to -27. The numbers in the bottom row multiply to -385. The numbers in the left column multiply to -66. The numbers in the middle column multiply to -135. The numbers in the right column multiply to 84. The sum of the integers in the 2 by 2 square at the top left of the grid is -7.
December 11, 2025 at 11:47 AM
mikejacobs.bsky.social
As I finished my daily run in the dark today I could smile to myself. Here in Oshawa, today is the day where the sun begins to set a little bit later each day (even though the day length is still getting shorter). It's only an extra second but it feels great!!
A table showing the sunrise times, sunset times and day lengths for Oshawa, Ontario. The data for Wednesday December 10th shows that the sunset is one second later than the previous day.
December 10, 2025 at 10:54 PM
mikejacobs.bsky.social
Start your day with this #yohaku. Fill in cells with 9 different factors of 198 to get totals shown in each row/column. #mathsky #iTeachMath
Use 9 different factors of 198 in a 3 by 3 grid. The numbers in the top row add to 53. The numbers in the middle row add to 23. The numbers in the bottom row add to 29. The numbers in the left column add to 45. The numbers in the middle column add to 43. The numbers in the right column add to 17.
December 10, 2025 at 11:50 AM
mikejacobs.bsky.social
Start your day with this #yohaku. Fill in cells with 9 different whole numbers to get products shown in each row/column. More free puzzles and books/ebooks for all ages can be found at yohaku.ca
#mathsky #iTeachMath
Use 9 different whole numbers in a 3 by 3 grid. The numbers in the top row multiply to 156. The numbers in the middle row multiply to 72. The numbers in the bottom row multiply to 240. The numbers in the left column multiply to 78. The numbers in the middle column multiply to 540. The numbers in the right column multiply to 64.
December 9, 2025 at 12:14 PM
mikejacobs.bsky.social
Start your week with this #yohaku. Fill in cells with 9 different factors of 306 to get totals shown in each row/column. #mathsky #iTeachMath
Use 9 different factors of 306 in a 3 by 3 grid. The numbers in the top row add to 122. The numbers in the middle row add to 49. The numbers in the bottom row add to 55. The numbers in the left column add to 62. The numbers in the middle column add to 27. The numbers in the right column add to 137.
December 8, 2025 at 12:04 PM
Reposted by Mike Jacobs
davidpetro314.bsky.social
[New Post] Ontario Math Links - My favourite #math related links from this week:

ontariomath.blogspot.com/2025/12/math...

Links and help from @amplifyeducation.bsky.social @themathguru.bsky.social @mikejacobs.bsky.social @howiehua.bsky.social @ganeshuor.bsky.social and more
December 7, 2025 at 2:26 PM
mikejacobs.bsky.social
Here's a #yohaku to take you into the weekend. Fill in cells with 16 different factors of 336 to get totals shown in each row/column AND shaded cells contain triangle numbers. #mathsky #iTeachMath
Use 16 different factors of 336 in a 4 by 4 grid. The numbers in the top row add to 15. The numbers in the second row add to 45. The numbers in the third row add to 111. The numbers in the bottom row add to 163. The numbers in the left column add to 90. The numbers in the second column add to 98. The numbers in the third column add to 112. The numbers in the right column add to 34. The central four cells contain triangle numbers.
December 5, 2025 at 12:11 PM
mikejacobs.bsky.social
Try this shady #yohaku. Fill in cells with 9 different integers to get products shown in each row/column AND sum of 4 shaded cells is -13. #mathsky #iTeachMath
Use 9 different integers in a 3 by 3 grid. The numbers in the top row multiply to -222. The numbers in the middle row multiply to -108. The numbers in the bottom row multiply to 52. The numbers in the left column multiply to -333. The numbers in the middle column multiply to -144. The numbers in the right column multiply to 26. The sum of the integers in the 2 by 2 square at the top left of the grid is -13.
December 4, 2025 at 12:05 PM
mikejacobs.bsky.social
Start your day with this #yohaku. Fill in cells with 9 different factors of 456 to get totals shown in each row/column. #mathsky #iTeachMath
Use 9 different factors of 456 in a 3 by 3 grid. The numbers in the top row add to 74. The numbers in the middle row add to 69. The numbers in the bottom row add to 101. The numbers in the left column add to 34. The numbers in the middle column add to 114. The numbers in the right column add to 96.
December 3, 2025 at 12:05 PM
mikejacobs.bsky.social
Start your day with this #yohaku. Fill in cells with 9 different whole numbers to get products shown in each row/column. More free puzzles and books/ebooks for all ages can be found at yohaku.ca
Use 9 different whole numbers in a 3 by 3 grid. The numbers in the top row multiply to 42. The numbers in the middle row multiply to 54. The numbers in the bottom row multiply to 572. The numbers in the left column multiply to 198. The numbers in the middle column multiply to 56. The numbers in the right column multiply to 117.
December 2, 2025 at 11:54 AM
mikejacobs.bsky.social
Start your week with this #yohaku. Fill in cells with 9 different factors of 315 to get totals shown in each row/column. #mathsky #iTeachMath
Use 9 different factors of 315 in a 3 by 3 grid. The numbers in the top row add to 15. The numbers in the middle row add to 87. The numbers in the bottom row add to 57. The numbers in the left column add to 27. The numbers in the middle column add to 61. The numbers in the right column add to 71.
December 1, 2025 at 12:06 PM
mikejacobs.bsky.social
Had an interview yesterday: hopefully I will be selected as a volunteer at the @fifaclubworldcup.bsky.social in Toronto next year!
A bearded man in a white England football jersey holding an oversized football in front of a photo of the Toronto skyline.
November 30, 2025 at 10:54 PM
mikejacobs.bsky.social
Latha Naomh Anndra sona dhuibh!
Happy St. Andrew's Day🏴󠁧󠁢󠁳󠁣󠁴󠁿
A Scottish flag flying on a balcony with a snowy background.
November 30, 2025 at 4:13 PM