Grade 3 - Patterning and Algebra
Standard 3.PA.2 - Compare subtraction equations to find the related fact with numbers up to 1000.
Included Skills: Subtraction, Number Properties
Expressions and Equality • determine, through investigation, the inverse relationship between addition and subtraction (e.g., since 4 + 5 = 9, then 9 - 5 = 4; since 16 - 9 = 7, then 7 + 9 = 16); • determine, the missing number in equations involving addition and subtraction of one- and two-digit numbers, using a variety of tools and strategies (e.g., modelling with concrete materials, using guess and check with and without the aid of a calculator) (Sample problem: What is the missing number in the equation 25 - 4 = 15 + ?); • identify, through investigation, the properties of zero and one in multiplication (i.e., any number multiplied by zero equals zero; any number multiplied by 1 equals the original number) (Sample problem: Use tiles to create arrays that represent 3 x 3, 3 x 2, 3 x 1, and 3 x 0. Explain what you think will happen when you multiply any number by 1, and when you multiply any number by 0.); • identify, through investigation, and use the associative property of addition to facilitate computation with whole numbers (e.g., "I know that 17 + 16 equals 17 + 3 + 13. This is easier to add in my head because I get 20 + 13 = 33.").