
Math Clocks
based on JRMF Activities
New in December 2021: SB Crafts has a brandnew collection of JRMF clocks, each featuring a design based on a popular math activity from the Julia Robinson Mathematics Festival.
JRMF is a nonprofit organization whose mission is to inspire joy in mathematics through math festivals. During the pandemic, JRMF has developed many highquality, accessible, online apps as alternatives to the handson materials at inperson festivals. Each clock is based on one of these apps.


Note: Clicking
on a picture of a clock
opens a new window containing a larger
picture of that clock, so that you can
see it and read about it simultaneously.
(Sorry about the shadows!)


Note: Clicking
on the links below takes you to the JRMF website. We encourage you to explore the activities.



River Crossings Clock 
The classic River Crossing Puzzle  involving a wolf, a goat and a cabbage  is centuries old, but this JRMF variation is less than a year old. If left unguarded, each Neyed monster will eat the Keyed monster, where K is the largest proper factor of N.
The thin lines are a graphical representation of these relationships, which aids in finding a solution to the puzzle.

River Ccrossings JRMF Activity 




Ladybugs Clock 
Starting with Ladybug #1 and proceeding in order, the goal is to fit as many ladybugs as possible onto the two leaves, so that no two ladybug numbers on a leaf add up to the number of another ladybug on that leaf.
This activity was baded on the Bubbling Cauldrons activity from Math Pickle.

Ladybugs JRMF Activity 




Colored Loops Clock 
Colored Loop Puzzles involve coloring and numbering arrorws so each color represents a separate loop with the numbers giving the sizes of the steps in the loop.
This clock is actually a new Colored Loops Puzzle itself! The unnumbered arrows can be numbered according to the rules of the activity, but, unlike the alreadynumbered arrows, none of them will correspond to the clock's hours.

Colored Loops JRMF Activity 




Tippy Toads Clock 
This activity involves finding ways to place toads in the sectors so that the lilypad is balanced and doesn't dip into the water. The big toads weigh twice as much as the little ones.
Is the configuration shown in balance? If not, which direction will it tip?

Tippy Toads JRMF Activity 



The introductory price of the clocks, good through the end of 2021, is $50. (Gift certificates purchased in December, good for any JRMF clock, will be honored through 2022.) SB Crafts will donate 30% of all proceeds to JRMF, to help spread the joy of math.
For ordering information or any questions, see the bottom of the main SB Crafts Clocks web page or just email us.
