Numbers on a Number Line
Aligned to 2.MD.B.6 — Common Core State Standards for Mathematics.
What this lesson teaches
A number line is like a ruler. You can hop forward to add and hop backward to subtract, landing on the answer.
Worked examples
Example 1
Start at 30 on the number line. Hop forward 20 to add: 30 + 20 lands on 50.
Example 2
Start at 45 and hop back 20 to subtract: 45 − 20 lands on 25.
Example 3
Hops do not have to be the same size. From 38 you can hop 2 to reach 40, then hop 10 more to land on 50 — that is 38 + 12.
Practice questions
- Start at 15 and hop forward 10. Where do you land?
- Start at 40 and hop back 25. Where do you land?
- On a number line, what number is 30 more than 45?
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
Números en la recta numérica
Una recta numérica es como una regla. Puedes saltar hacia adelante para sumar y hacia atrás para restar, cayendo en la respuesta.
Ejemplo 1: Empieza en 30 en la recta numérica. Salta 20 hacia adelante para sumar: 30 + 20 cae en 50.
Ejemplo 2: Empieza en 45 y salta 20 hacia atrás para restar: 45 − 20 cae en 25.
Ejemplo 3: Los saltos no tienen que ser del mismo tamaño. Desde 38 puedes saltar 2 para llegar a 40, y luego 10 más para caer en 50 — eso es 38 + 12.
More Measurement & Data lessons
Teach this lesson today
An AI tutor that guides with questions instead of just giving answers — all K–12 core subjects, every child in the family.
Start free — no card required