Estimate to the nearest ten

key notes :

Understanding Rounding:

Explain that estimating to the nearest ten means rounding numbers to the closest multiple of ten (like 10, 20, 30, etc.).

Identifying Tens:

Help students recognize the tens place in a two-digit number (e.g., in 43, the number 4 is in the tens place).

Rounding Rules:

  • If the number in the ones place is 5 or more, round up (e.g., 47 becomes 50).
  • If the number in the ones place is less than 5, round down (e.g., 42 becomes 40).

Visual Aid: Use a number line to visually show how numbers round to the nearest ten.

Examples:

  • Estimate 37 to the nearest ten → 40.
  • Estimate 82 to the nearest ten → 80.

Practical Application:

Give real-world examples, like estimating the number of people in a group or the number of books on a shelf, and ask students to round them to the nearest ten.

Learn with an example

🪂 How many marbles are there? Estimate.

  • about 40
  • about 80
  • This is a group of ten marbles:
  • There are not enough marbles to make 8 groups of 10. There are fewer than 80 marbles. There are about 40 marbles.

🪂 How many marbles are there? Estimate.

  • about 20
  • about 70
  • This is a group of ten marbles:
  • There are not enough marbles to make 7 groups of 10. There are fewer than 70 marbles. There are about 20 marbles.

🪂 How many marbles are there? Estimate.

  • about 30
  • about 60
  • This is a group of ten marbles:
  • There are not enough marbles to make 6 groups of 10. There are fewer than 60 marbles. There are about 30 marbles.

Let’s practice!