Measuring and ordering lengths (grade 1) · lesson

Order by length

Tap each one to count it

💡 Line things up at one end. Then put them in order.

Start them all at the same line. Look at the other ends.

The one that ends first is shortest. The one that ends last is longest.

🧠 How to think about it

Crayon 4 cubes, brush 7, pen 9. In order: 4, 7, 9. The brush is in the middle.

🏡 Try it at home

Line up 3 shoes from the closet, short to long.

💡 A is longer than B. B is longer than C. So A is longer than C.

Jo is taller than Max. Max is taller than Ana.

So Jo is taller than Ana, and Jo is the tallest.

🧠 How to think about it

Find the one in the middle. The one bigger than the middle is the biggest. The one smaller is the smallest.

🏡 Try it at home

Is the couch longer than the table? Use a string to check. Measure both with the string.

Tap each one to count it

💡 Count how many same-size units fit end to end.

Line up cubes along a pencil. If 6 fit, the pencil is 6 cubes long.

Use units that are all the same size.

🧠 How to think about it

Book 8 cubes, pencil 5 cubes. The book is 3 cubes longer. 8 − 5 = 3.

🏡 Try it at home

Measure a book with paper clips or spoons. How many fit end to end?

💡 Units must touch end to end, with no gaps and no overlaps.

Gaps leave parts out. Then your number is too small.

Overlaps count parts twice. Then your number is too big.

🧠 How to think about it

Look at your line of units. Do they touch? Do any lie on top of each other? Fix it, then count.

🏡 Try it at home

Measure a table with shoes. Leave gaps once and touch once. Which count is right?