Numbers on a number line
Represent whole numbers as lengths on a number line and represent sums and differences within 100 on a number line diagram
What a learner can do afterwards
- Place whole numbers on a number line with equally spaced points
- Show an addition as a jump forward on the number line (e.g. 38 + 27 shown as jumps)
- Show a subtraction as a jump backward on the number line
1 · Read
A number line is a straight line with numbers sitting on it in order. The gap between one number and the next always stays the same size. Small numbers are on the left, and bigger numbers are on the right.
Mia starts at 38 and wants to add 27. She jumps forward 20, landing on 58. Then she jumps forward 7 more, landing on 65. So 38 + 27 = 65.
Now try 84 minus 26. Start at 84 and jump backward 20, landing on 64. Jump back 6 more, landing on 58. So 84 - 26 = 58.
Whichever way you jump, the number line keeps track for you. Where you land after your jumps is the answer.
Adding is a jump forward on the number line, subtracting is a jump backward, and where you land is your answer.
More to read
36.2: Points on the Number Line
A number line is a road with every house in order. Peg 5 halfway between 0 and 10, and 70 near 68 when marks jump by tens. Equal gaps between marks keep the road honest: if the steps wobble, the landings lie. Walk the road with a finger before trusting any dot.
1.2 Add Whole Numbers
Addition is a forward hop along the road. Start at 38, spring 20 to 58, then bounce 7 more to 65. Big hops first, small hops second: tens carry you far while ones place you exactly. Draw the curved arrows above the line so each hop shows its size.
1.3 Subtract Whole Numbers
Subtraction is the same road walked backwards. Start at 82, step 20 back to 62, then 5 back to 57. Face left, count the steps, and land softly on the answer. Forward hops add, backward hops take away, and the line never forgets a step.
Explore more
2 · Watch
En anglaisTake it off screen
Where it sits
Learn first
Nothing; this is a starting point.
Optional connections
This opens up
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
17 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.