Discover why you can test for divisibility by 3 and 9 by adding digits, and prove it.
Investigate why digit sums reveal divisibility by 3 and 9, and prove the rule using place value.
Discover systematic ways to count arrangements and selections, and use them to solve olympiad-style problems.
50 to 80 min · 3 materialsView projectDecide whether a route can cross every bridge once and discover the rule that solves every such puzzle.
50 to 80 min · 4 materialsView projectDraw polygons on dot paper, count points, and discover a formula for area using only dots.
50 to 90 min · 4 materialsView projectExplore arithmetic that wraps around like a clock and use it to solve remainder and last digit puzzles.
50 to 80 min · 3 materialsView projectEncrypt with a keyword and break the cipher by splitting the message and using frequency analysis on each part.
1 to 1.7 hr · 4 materialsView projectMake secret messages with a Caesar cipher and crack coded messages using letter frequency.
40 to 70 min · 4 materialsView projectEduVistaHQ.com · Learn • Explore • Grow