Add and subtract 1 to and from a 2-digit number crossing the tens boundary
I can add and subtract one to and from a two-digit number crossing the tens boundary.
Add and subtract 1 to and from a 2-digit number crossing the tens boundary
I can add and subtract one to and from a two-digit number crossing the tens boundary.
These resources will be removed by end of Summer Term 2025.
Lesson details
Key learning points
- Finding one more is the same as adding one; finding one less is the same as subtracting one.
- Numbers that are one more or one less than each other have a difference of one.
- When one is added to a number with a ones digit of 9, the next multiple of ten will be reached.
- When one is subtracted from a multiple of ten, the number reached will have a ones digit of 9
- When one ten is changed for ten ones, or ten ones for one ten, it is called regrouping.
Keywords
One more - One more is when there is a greater amount by one or another item in the set.
One less - One less is when there is a smaller value by one.
Difference - The result of subtracting one number from another, How much one number differs from another.
Decade - A group of ten numbers below one hundred, each with the same tens digit.
Regroup - To exchange ten ones for one ten or one ten for ten ones in order to calculate more easily.
Common misconception
Children may have difficulty finding one less than a multiple of ten saying, for example, one less than 60 is 69.
Refer to the order of the decades counting forwards and backwards and encourage visualisation of the decades on number lines and one hundred squares to support this. Help children to generalise about the number before a decade number ending in 9
To help you plan your year 2 maths lesson on: Add and subtract 1 to and from a 2-digit number crossing the tens boundary, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your year 2 maths lesson on: Add and subtract 1 to and from a 2-digit number crossing the tens boundary, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
We use learning cycles to break down learning into key concepts or ideas linked to the learning outcome. Each learning cycle features explanations with checks for understanding and practice tasks with feedback. All of this is found in our slide decks, ready for you to download and edit. The practice tasks are also available as printable worksheets and some lessons have additional materials with extra material you might need for teaching the lesson.
The assessment exit quiz will test your pupils' understanding of the key learning points.
Our video is a tool for planning, showing how other teachers might teach the lesson, offering helpful tips, modelled explanations and inspiration for your own delivery in the classroom. Plus, you can set it as homework or revision for pupils and keep their learning on track by sharing an online pupil version of this lesson.
Explore more key stage 1 maths lessons from the Adding and subtracting ones and tens to and from 2-digit numbers unit, dive into the full secondary maths curriculum, or learn more about lesson planning.
Licence
Lesson video
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Starter quiz
6 Questions
35
33
35
Exit quiz
6 Questions
