Grade 5-1
45 problems
Maximize or minimize a mixed expression
Insert parentheses to change the result
Simplify calculations by regrouping
Ancient Egyptian fair sharing of loaves
Several ways to build unit-fraction sums
Unit fractions from the denominator's divisors
Compare the sizes of fractions
Build fractions from number cards
Simplify a long fraction sum
How perimeter and area are related
Perimeter of a rectilinear figure
Perimeter of joined and cut rectangles
Area of a complicated composite figure
Area of overlapping figures
Area of pieces that split a rectangle
Pick's theorem from dot counts
Measure a figure in copies of a unit piece
Move a figure to make its area easy
Equal-area triangles between parallel sides
Straighten a border without changing areas
Trapezoid area found four different ways
Four fours: reach several large targets
Four fours: hit a target number
Place number cards to make an equation true
Erase one plus sign to hit the target
Insert plus and minus signs to make 100
Use odd and even to rule out totals
Append digits to hit several multiples
Divisibility tests for 2 through 9
Test for 11 by alternating digit sum
Count divisors with a Hasse diagram
Count primes with the sieve of Eratosthenes
Prime factorization two ways
Lockers left open by divisor-count parity
Perfect squares from even prime exponents
Trailing zeros from pairs of 2 and 5
The Euclidean algorithm for the GCD
Product equals GCD times LCM
GCD and LCM in tiling problems
Count a growing figure three ways
Who sits opposite in a circle
Regions of a circle cut by lines
Find the rule linking two numbers
Iterate a rule to a far term
Evaluate nested defined operations