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-20 -15 -10 -5 0 5 10 Integer work mat 15 20 How to use the “Integer work mat” • Each blue counter is worth +1 • Each red counter is worth -1 (in other words ‘the opposite of 1’) • If the mathematical operation is addition, this means putting something down onto the mat • If the mathematical operation is subtraction, this means removing something from the mat First, let’s look at ‘addition’… Start with three positive counters Add to this by putting down onto the mat… One negative counter 3 + −1 Start with three positive counters Add to this by putting down onto the mat… Two negative counters 3 + −2 Start with three positive counters Add to this by putting down onto the mat… Five negative counters 3 + −5 Start with three negative counters Add to this by putting down onto the mat… Two negative counters −3 + −2 Start with three negative counters Add to this by putting down onto the mat… Two positive counters −3 + 2 Start with three negative counters Add to this by putting down onto the mat… Five positive counters −3 + 5 Key Questions about Addition: 1. Which direction do you move on the number line when adding a positive integer? 2. Which direction do you move on the number line when adding a negative integer? Practice these addition situations: 1) 2 + 7 = 2) 2 + −7 = 3) −2 + 7 = 4) −2 + −7 = 5) −4 + 2 = 6) −4 + −2 = 7) −6 + −1 = 8) 5 + −11 = Now, let’s look at ‘subtraction’… What does it mean to ‘subtract’ something? Subtract from this by removing from the mat… Start with three positive counters One positive counter 3−1 Subtract from this by removing from the mat… Start with three positive counters Five positive counters 3−5 Subtract from this by removing from the mat… Start with three positive counters Five negative counters 3 − −5 Subtract from this by removing from the mat… Start with three positive counters One negative counter 3 − −1 Subtract from this by removing from the mat… Start with three negative counters One negative counter −3 − −1 Subtract from this by removing from the mat… Start with three negative counters One positive counter −3 − 1 Key Questions about Subtraction: 1. Which direction do you move on the number line when subtracting a positive integer? 2. Which direction do you move on the number line when subtracting a negative integer? Practice these subtraction situations: 1) 2 − 7 = 2) 2 − −7 = 3) −2 − 7 = 4) −2 − −7 = 5) 6 − 2 = 6) 6 − 10 = 7) −7 − −1 = 8) −4 − −11 =