Question 1: Opposites (2 points)
- The opposite of \(-13\) is \(13\).
- Opposites add to zero, so \(-18.5 + 18.5 = \)\(0\).
Scoring: 1 point for each correct answer.
Question 2: Equation from a Number Line (2 points)
The jump is \(8\) units right from \(-5\) and ends at \(3\).
\(-5 + 8 = 3\)
Scoring: 1 point for the correct addends \(-5\) and \(8\), 1 point for the sum \(3\).
Question 3: Adding Integers (2 points)
- \(14 – 9 = 5\), and \(-14\) has the larger absolute value, so \(-5\).
- Same signs: \(8 + 6 = 14\), so \(-14\).
Scoring: 1 point for each correct sum.
Question 4: Subtracting Integers (2 points)
- \(7 + (-15) = \)\(-8\).
- \(-3 + 9 = \)\(6\).
Scoring: 1 point for each correct difference.
Question 5: Decimals and Fractions (2 points)
- \(2.75 – 1.5 = 1.25\), with the sign of \(-2.75\): \(-1.25\).
- \(-\frac{2}{4} + (-\frac{3}{4}) = \)\(-\frac{5}{4}\), or \(-1\frac{1}{4}\).
Scoring: 1 point for each correct value. Accept equivalent forms such as \(-1\frac{1}{4}\).
Question 6: Overnight Temperatures (2 points)
- \(-8 + 15 = 7\), so \(7^{\circ}\text{F}\).
- \(7 – 11 = -4\), so \(-4^{\circ}\text{F}\).
Scoring: 1 point for each correct temperature with the correct sign.
Question 7: Distance Between Points (3 points)
- \(|-7.5 – 4| = |-11.5| = 11.5\). The distance is 11.5 units.
- \(4 + 5.5 = \)\(9.5\).
Scoring: 2 points for part (a): 1 for a correct absolute value expression such as \(|-7.5 – 4|\), 1 for \(11.5\). 1 point for part (b).
Question 8: Account Balance (3 points)
- \(-18.40 + 50 = 31.60\), so \(\$31.60\).
- \(31.60 – 37.85 = -6.25\), so \(-\$6.25\).
- The opposite of \(-6.25\) is \(6.25\), so he must deposit \(\$6.25\).
Scoring: 1 point for each part.
Question 9: Find the Error (2 points)
- Liam subtracted \(2\) instead of subtracting \(-2\). Subtracting a negative number means adding its opposite, so the expression is \(-6 + 2\).
- \(-6 + 2 = \)\(-4\).
Scoring: 1 point for a correct explanation (adding the opposite), 1 point for \(-4\).
20 points

See every chapter on the Grade 7 math page.

