Ex: Commutative property Sum does not change when the order of the addends are switched. Ex: Plus 0 (additive identity) Adding zero to a number does not affect the total. Ex: 1 + 0 = 1; 2 + 0 = 2; 3 + 0 = 3; etc. Ex: 1 = 1 + 0; 2 = 2 + 0; 3 = 3 + 0; etc. Plus 1 Adding 1 related to sequential counting Ex: 9 + 1 = 10 or 10 = 9 + 1 Counting on Begin with one addend and count on the amount of the other addend. Ex: Recall With Automaticity BASIC FACTS TO SUBTRACT WITHIN 20 Including, but not limited to: Whole numbers Counting (natural) numbers the set of positive numbers that begins at one and increases by increments of one each time {1, 2, 3, ..., n} – Whole numbers the set of counting (natural) numbers and zero {0, 1, 2, 3, ..., n} – Automaticity executing a basic fact with little or no conscious effort – Subtraction Difference the remaining amount after the subtrahend has been subtracted from the minuend – Minuend a number from which another number will be subtracted – Subtrahend a number to be subtracted from a minuend – Subtraction of whole numbers within 20 Solutions recorded with a number sentence Number sentence a mathematical statement composed of numbers, and/or an unknown(s), and/or an operator(s), and an equality or – inequality symbol Equal sign at beginning or end Ex: 6 = 10 4; 10 4 = 6 – – Decompose numbers to break a number into parts or smaller values – Basic fact subtraction strategies leading to automaticity
Ex: Commutative property Sum does not change when the order of the addends are switched. Ex: Plus 0 (additive identity) Adding zero to a number does not affect the total. Ex: 1 + 0 = 1; 2 + 0 = 2; 3 + 0 = 3; etc. Ex: 1 = 1 + 0; 2 = 2 + 0; 3 = 3 + 0; etc. Plus 1 Adding 1 related to sequential counting Ex: 9 + 1 = 10 or 10 = 9 + 1 Counting on Begin with one addend and count on the amount of the other addend. Ex: Recall With Automaticity BASIC FACTS TO SUBTRACT WITHIN 20 Including, but not limited to: Whole numbers Counting (natural) numbers – the set of positive numbers that begins at one and increases by increments of one each time {1, 2, 3, ..., n} Whole numbers – the set of counting (natural) numbers and zero {0, 1, 2, 3, ..., n} Automaticity – executing a basic fact with little or no conscious effort Subtraction Difference – the remaining amount after the subtrahend has been subtracted from the minuend Minuend – a number from which another number will be subtracted Subtrahend – a number to be subtracted from a minuend Subtraction of whole numbers within 20 Solutions recorded with a number sentence Number sentence – a mathematical statement composed of numbers, and/or an unknown(s), and/or an operator(s), and an equality or inequality symbol Equal sign at beginning or end Ex: 6 = 10 – 4; 10 – 4 = 6 Decompose numbers – to break a number into parts or smaller values Basic fact subtraction strategies leading to automaticity