Understand x 100 and ÷ 100 as inverses - Teaching Presentation - Year 3

This presentation provides three days of teaching that cover the objectives:

• Understand multiplying and dividing by 10 and 100 (3-digit numbers) as inverse operations.

It includes starter activities, whole class teaching, group activities, practice sheets and mastery questions. It can be used on a variety of interactive whiteboards.

Day 1 Teaching
Children copy a place value grid from the board to their whiteboards. They use digit cards to show 30 on it. Demonstrate multiplying by 10 and dividing by 10. Repeat to multiply 25 by 10 and to divide 270 by 10. Continue with other examples.

Day 2 Teaching
Children write 4 on a place value grid on their whiteboards, they show 4 × 10 then 4 × 100. Point out that the digits are shifting two places to the left when we multiply by 100. Repeat with 7 × 10 and 7 × 100. Then divide by 100.

Day 3 Teaching
Show a function machine (see resources). Children think what is happening inside the machine. Use the machine to multiply by 10 or 100, and then to ‘undo’ this by dividing by 10 or 100. Use the machine to demonstrate these inverse operations.

This teaching is part of Hamilton’s Year 3 Place Value and Money block. Each Hamilton maths block contains a complete set of planning and resources to teach a term’s worth of objectives for one of the National Curriculum for England’s maths areas.