Calculations

Objectives

To round 2-digit numbers to the nearest 10.

Resources

Abacus Workbook 2 | Whiteboard and pen | Rounding (YouTube) | 1–9 dice

Vocabulary

rounding | nearest 10

Today's Lesson

Introduction

Before you start the lesson, watch this Recap Video with your student.

Remind your student that in the last lesson they were thinking about which multiple of 10 a 2-digit number is closer to. Explain that we call this ‘rounding to the nearest 10’.

Using your whiteboard and pen, draw a number line 0-10. Ensure that the numbers are evenly spread along the number line. Point to 3.

Is this closer to 0 or 10?

Now repeat for other numbers.

After you have explored all other numbers, spend time talking about the number 5. Explain that although 5 is in the middle, mathematicians have decided (so that we all do the same thing) that we will round 5 up to the 10 above.

Write 33 and ask which 10s numbers this is between.

Now using your whiteboard and pen, draw a number line from 30-40. Mark 33 on the line.

Ask:

Is this closer to 30 or 40?
What is 33 rounded to the nearest 10?

Repeat for 38, 32, then 35 to emphasise that when the digit in the ones column is 5 or above, we round up.

Watch the videoon rounding.

Main Activity

Working as a pair, generate a 2-digit number by rolling a 1–9 dice twice.

Then, round your number to the nearest 10 and discuss the answer together.  

Challenge your student to see how quickly they can round numbers.

Extra Challenge

Ask your student to design a poster or a series of instructions explaining rounding to the nearest 10. They should include many examples, including those ending with 5.

Workbook

To help your student consolidate their learning from today, please ask them to complete the activities on page 32 of Abacus Workbook 2.

Citations

[1] www.youtube.com [2] www.youtube.com