Inequality Range Membership
Decide or count the whole numbers that satisfy 이상/이하/초과/미만 (greater/less than or equal, strictly greater/less) boundary conditions, often as the overlap of two ranges on a number line.
grade 6–8 ExpressionsNumber systemGeometry systematicvisual
Progression (11)
g6 1. Overlap of two ranges on a number line ExpressionsNumber system
g6 2. Inclusive vs exclusive range boundaries ExpressionsNumber system
g6 3. Multiplying both sides keeps the inequality direction ExpressionsNumber system
g6 4. Find the number before it was rounded ExpressionsNumber systemBase-ten numbers
g6 5. Simplify the expression before comparing Number systemExpressions
g6 6. Rounding is an up or a down Number systemExpressionsBase-ten numbers
g7 7. Rounding to n means a half-open interval Base-ten numbersExpressions
g7 8. Turn decimal-digit clues into inequalities ExpressionsNumber system
g7 9. Triangle inequality bounds isosceles legs GeometryExpressions
g8 10. Turn leading digits into an inequality Number systemExpressions
g7 11. Bound the smallest variable, then list cases ExpressionsNumber system
Bridges to competition (1)
Reasoning problems that extend this idea toward competition:
Fractions meeting given conditions Counting