Kindergarten: Number Line

Warm up with a quick recall on the board. Model jumps along a marked line for counting on, addition and subtraction. Keep the intervals equal and start jumps from the correct point.

A number line is a straight line with numbers marked at equal spaces. It turns numbers into positions and distances, which makes counting, comparing, adding, subtracting and rounding visual. Because the spacing is even, the gap between marks always stands for the same amount, and that even spacing is the key idea. Model the method clearly, thinking aloud:

• Start with a marked, evenly spaced line and read the labelled points before finding unlabelled ones.
• Teach that equal gaps mean equal steps: count the intervals (the jumps), not the marks, to measure a distance.
• Find a missing number by working out the step size from two known marks, then counting on.
• Model addition as jumps to the right and subtraction as jumps to the left, landing on the answer.
• Use it for rounding and comparing: a number is nearer whichever labelled mark it sits closer to.

Do the first few questions of the practice worksheet together, one child explaining each step. Check for understanding before releasing the class to work alone.

Students complete the worksheet independently. Hand out the three difficulty levels below so every child works at the right stretch.

Circulate and look for these, they are the usual sticking points:

• Counting the marks instead of the gaps when measuring a jump.
• Assuming the line starts at zero or steps up in ones without checking the labels.
• Spacing numbers unevenly when drawing a line of their own.
• Losing the step size when the marks go up in 2s, 5s or 10s.
• Counting the starting mark as one jump, and unequal spacing between marks.

Pull the class back together. Ask one child to explain number line in their own words, pose a single check question everyone answers on a mini whiteboard, and name what you will build on next lesson.

Use the independent worksheet as the evidence. A child who can complete it accurately and explain one answer has met the objective; anyone who cannot needs the easier level and a short reteach next session.