Question

25
nso.4.1
add integers with the same sign and with opposite signs using number lines by drawing rays above the number line (l3)
using a number line, model the expressions below:
-7 + 4 8 + (-5) -6 + (-2)
using a number line, model the expressions below:
-3 + 7 5 + (-9) -4 + (-3)

Explanation:

Step1: Model \(-7 + 4\)

Start at \(-7\) on the number line. Since we add \(4\) (positive), move \(4\) units to the right. \(-7 + 4=-3\).

Step2: Model \(8 + (-5)\)

Start at \(8\). Add \(-5\) (negative), so move \(5\) units to the left. \(8+(-5) = 3\).

Step3: Model \(-6 + (-2)\)

Start at \(-6\). Add \(-2\) (negative), move \(2\) units to the left. \(-6+(-2)=-8\).

Step4: Model \(-3 + 7\)

Start at \(-3\). Add \(7\) (positive), move \(7\) units to the right. \(-3 + 7 = 4\).

Step5: Model \(5 + (-9)\)

Start at \(5\). Add \(-9\) (negative), move \(9\) units to the left. \(5+(-9)=-4\).

Step6: Model \(-4 + (-3)\)

Start at \(-4\). Add \(-3\) (negative), move \(3\) units to the left. \(-4+(-3)=-7\).

Answer:

For \(-7 + 4=-3\), \(8 + (-5)=3\), \(-6 + (-2)=-8\), \(-3 + 7 = 4\), \(5 + (-9)=-4\), \(-4 + (-3)=-7\) (and the number - line models involve starting at the first integer and moving the number of units corresponding to the second integer, right for positive, left for negative).