Operations with Integers
Aligned to 7.NS.A.1 — Common Core State Standards for Mathematics.
What this lesson teaches
Adding a negative moves left on the number line; subtracting a negative moves right (it's the same as adding). For multiplication/division, same signs give positive, different signs give negative.
Worked examples
Example 1
−3 + (−5) = −8 (both push left). −4 × 3 = −12 (different signs → negative). −6 − (−2) = −6 + 2 = −4.
Example 2
−12 ÷ (−4) = 3. Two negatives divided give a positive, just as they do when multiplied.
Example 3
Subtracting a negative adds: 5 − (−3) = 5 + 3 = 8. On a number line, you turn around twice and end up moving right.
Practice questions
- Compute −7 + 4.
- Compute −5 × −6.
- Compute 3 − 8, then −2 − (−9).
Watch the lesson
Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.
▶ Watch this lessonEn español
Operaciones con Números Enteros
Sumar un número negativo nos mueve hacia la izquierda en la recta numérica; restar un número negativo nos mueve hacia la derecha (es lo mismo que sumar). En la multiplicación y división, signos iguales dan un resultado positivo, y signos diferentes dan un resultado negativo.
Ejemplo 1: −3 + (−5) = −8 (ambos mueven hacia la izquierda). −4 × 3 = −12 (signos diferentes → negativo). −6 − (−2) = −6 + 2 = −4.
Ejemplo 2: −12 ÷ (−4) = 3. Dos negativos divididos dan positivo, igual que al multiplicar.
Ejemplo 3: Restar un negativo suma: 5 − (−3) = 5 + 3 = 8. En la recta numérica giras dos veces y acabas moviéndote a la derecha.
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