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Grade 7

Positive and negative numbers practice

Signed numbers are the first topic of secondary-school maths and the basis of every later calculation. Master the sign rules.

Basic, Standard, Advanced: Grade 7 · Term 1

Math problem generator

Level

Addition and subtraction

Adding

Same signs: add the absolute values and keep the sign. (−5)+(−3)=−8(-5) + (-3) = -8

Different signs: subtract the smaller absolute value from the larger and take the sign of the number with the larger absolute value. (+8)+(−6)=2(+8) + (-6) = 2

To subtract, add the opposite: (+4)−(−7)=(+4)+(+7)=11(+4) - (-7) = (+4) + (+7) = 11.

With many terms, drop the brackets and group the positive and negative terms:

−3+8−(−5)−9=−3+8+5−9=13−12=1-3 + 8 - (-5) - 9 = -3 + 8 + 5 - 9 = 13 - 12 = 1

Multiplication and division

Sign rules

Same signs give a positive product or quotient; different signs give a negative one. With several factors, an even number of negatives gives ++ and an odd number gives −-.

Example: (−2)×3×(−5)=30(-2) \times 3 \times (-5) = 30. Division can be written as multiplication by the reciprocal: (−34)÷98=−23\left(-\frac{3}{4}\right) \div \frac{9}{8} = -\frac{2}{3}.

Powers and mixed operations

(−3)2=(−3)×(−3)=9(-3)^2 = (-3) \times (-3) = 9, but −32=−(3×3)=−9-3^2 = -(3 \times 3) = -9. Check what the exponent applies to.

Order

powers and brackets, then multiplication and division, then addition and subtraction

−32+(−2)3×(−3)=−9+24=15-3^2 + (-2)^3 \times (-3) = -9 + 24 = 15

The distributive law (a+b)×c=a×c+b×c(a + b) \times c = a \times c + b \times c avoids common denominators when a bracket of fractions is multiplied by an integer.