Bonds to multiples of 100

Objectives

To work out strategies for finding missing numbers.

To make a connection between addition and subtraction within mathematical sentences.

Resources

Today's Lesson

Times Tables

Learning the times tables is an important skill in Maths as knowledge of these is used in a wide range of areas. For this reason, we recommend that students practise their tables at the beginning of every lesson**.** As part of your Wolsey Hall course, you also have free access to the superb subscription-based website Times Table Rock Stars (TT Rockstars) which we encourage you use 5 times a week.

Tip: For help logging in to TT Rockstars for the first time, please follow the guidance found in How to access TT Rockstars.

If you do not have access to your login details, please contact your SPM.

Main Activity

As a mental warm up, your student should recap number bonds to 10 and 100. Depending on your student’s ability, you may wish to provide them with a 100 square to help. E.g. 37 + ? = 100. Your student should count from 37 to 40 (or use their knowledge that 7+3=10 so 37+3=40) and then count in 10s until they reach 100. They will then have the answer 63. If your student is confident in finding number bonds, ask them to access Number bonds (TopMarks)and choose ‘Number Bonds’ followed by ‘Make 100’ or ‘Make 100 (tens).

Turn to page 4 in Abacus 4 Textbook 1.

Look at the questions with your student and then watch Number bonds to 100 (YouTube) and Frog Method (YouTube) to help your student to understand how to find the missing answers.

Look back at P4 and discuss the first question. Note: Your student should understand how to find missing numbers in the middle of calculations using inverse facts,

E.g. 34 + ? = 100 is the same as 100 – 34 = ?

Strategy 1: Model the methods used in the videos using a 100 square and number line. Start on 34, count to 40 and then count to 100. Encourage your student to draw the number line and the jumps as this strategy can be used with larger numbers too.

Strategy 2: You student might also suggest using a number line to subtract 34 from 100.

Note: Counting on using a number line is often the preferred (and easier method) and results in less mistakes but allow your student to use whichever method they prefer.

Ask your student to complete Q1-12.

Questions 13-24 involve real-life problems but can be answered in exactly the same way as the previous questions. Model the first question with your student and ask them how they would work out the change. E.g. I go into a shop and buy a chocolate bar for 56p. I give the shopkeeper £1. How much change will I receive?

Note: It is important that your student knows that 100p = £1 and that the ‘change’ is the money you receive back from the shopkeeper. Ask your student what calculation they will need to complete to solve the problem.

E.g £1 – 56p

This can then be rewritten as 100p – 56p Your student should then recognise the calculation is simply 100-56. Remind them of the importance of including the £ or p symbols in their answer.

Ask your student to complete the remainder of the page.

Encourage your student to write one digit or mathematical symbol in each square of the paper. You may need to find paper with larger squares for younger students; 1 cm squares might be good to start with.

Citations

[1] www.youtube.com [2] youtu.be [3] www.youtube.com [4] www.youtube.com [5] www.topmarks.co.uk [6] app.mymaths.co.uk