Math Games

Grade 8 - Number Sense and Numeration

Standard 8.NSN.2 - Practice estimating the percents of numbers.

Included Skills:

Operational Sense
• solve multi-step problems arising from real-life contexts and involving whole numbers and decimals, using a variety of tools (e.g., graphs, calculators) and strategies (e.g., estimation, algorithms);
• solve problems involving percents expressed to one decimal place (e.g., 12.5%) and whole-number percents greater than 100 (e.g., 115%) (Sample problem: The total cost of an item with tax included [115%] is $23.00. Use base ten materials to determine the price before tax.);
• use estimation when solving problems involving operations with whole numbers, decimals, percents, integers, and fractions, to help judge the reasonableness of a solution;
• represent the multiplication and division of fractions, using a variety of tools and strategies (e.g., use an area model to represent 1/4 multiplied by 1/3);
• solve problems involving addition, subtraction, multiplication, and division with simple fractions;
• represent the multiplication and division of integers, using a variety of tools [e.g., if black counters represent positive amounts and red counters represent negative amounts, you can model 3 x (-2) as three groups of two red counters];
• solve problems involving operations with integers, using a variety of tools (e.g., two-colour counters, virtual manipulatives, number lines);
• evaluate expressions that involve integers, including expressions that contain brackets and exponents, using order of operations;
• multiply and divide decimal numbers by various powers of ten (e.g., "To convert 230 000 cm3 to cubic metres, I calculated in my head 230 000 � 106 to get 0.23 m3.") (Sample problem: Use a calculator to help you generalize a rule for dividing numbers by 1 000 000.);
• estimate, and verify using a calculator, the positive square roots of whole numbers, and distinguish between whole numbers that have whole-number square roots (i.e., perfect square numbers) and those that do not (Sample problem: Explain why a square with an area of 20 cm2 does not have a whole-number side length.).