Challenges
Problems worth getting stuck on
A small shelf of curious problems, gathered for every family here. Pick one, sit down together, and if it bites back, June can work through it with your child.
- Fractions
- Decimals
- Percent
- Equations
- Number sense
- Counting
- Divisibility
- Geometry
- Area
- Contest problems
- Word problems
- Mental math
9 of 21 challenges ·
Grade 3
Six ways to sit in a row
Rebuild the missing number, seat three friends in every possible order, and spot the one story that is not really four fours. For a child learning to list every case and read past the numbers.
3 problems
Every edge counts
A wizard's stars hide edges in their valleys, and a blank inside a sum turns addition around. For a child practicing careful counting and working backwards.
2 problems
Grade 5
The decimal point takes a walk
Shift the decimal point and a number changes by a surprising amount -- the trick is counting the nines hiding in the difference.
3 problems
The leftovers tell the story
Three division riddles where the remainder is the whole puzzle -- what is left over tells you what you started with.
3 problems
Six people, six days
Five people earn five thousand in five days, so six people in six days earn... six thousand, right?
1 problem
A thirtieth in three parts
Break 1/30 into three unit fractions, all with different denominators. There is more than one way -- checking a friend's answer is half the fun.
1 problem