Four Digit Numbers

Objectives

To understand the connection between calculations using 3 digit and 4 digit numbers and recognise when to ignore the thousands digit whilst calculating.

To gain confidence in an ability to work mathematically with larger numbers.

Resources

Abacus 4 Textbook 1 | Squared paper | Timestables (TopMarks) | Frog Method (YouTube)

Today's Lesson

Main Activity

As a mental warm up, continue to learn the 2 times table if necessary. Otherwise, practise the 4, 8 and 11 times tables.

Apply the ‘frog method’ to random numbers for number bonds up to 100s. Call out a random 2 or 3 digit number. Ask your student how many to the next 100. This is to be worked out by counting the bond to the next 10 from the ones digit, then counting multiples of 10 to the next 100 and adding the bond to 10 to this total. (Watch Frog Method (YouTube) as a reminder if required.)

For example:

234 + ? = 300

‘Jump’ from 234 to 240 by adding 6. Then ‘jump’ from 240 to 300 by counting up in 10s. We have added 60, then we

need to remember to add our 6 to this to find the answer 6 + 60 = 66. So:

234 + 66 = 300

Turn to page 7 in Abacus 4 Textbook 1.

Look at the calculations and the number lines. Point out that they are exactly the same sort of calculations as those on the previous page; the only difference is that there is a thousands digit in front of the number.

Watch the ‘Frog method within 10,000’ video.

Use Frog in the same way to solve these calculations. For example: 4737 + ____ = 4800

Start at 4737 then +3 to reach 4740 then + 60 to reach 4800. You have added 63 so your missing number is 63. Run through additional examples if required.

Ask your student to complete the page with the drawn number lines in exactly the same way as the previous page was completed.

Citations

[1] www.youtube.com [2] www.youtube.com [3] www.topmarks.co.uk