Error Intervals | I Do, We Do, You Do | Year 10 Maths Foundation | Print Free

Teach finding error intervals with this editable Year 10 Maths Foundation lesson. Pupils connect rounding accuracy to lower and upper bounds, write intervals using inequality notation and explain which endpoint values are included.

WHAT IS INCLUDED
• One editable 66-slide PowerPoint with answers.
• Six retrieval questions and six prerequisite questions, each with grouped answers.
• Key vocabulary and a number-line explanation of error intervals.
• Six I Do / We Do examples in three matched pairs, using different values and worked answers.
• Twenty individual AFL questions, each immediately followed by its answer.
• Thirty-six whole-class practice questions on one slide, with all answers on one slide.
• A single differentiated page containing 14 Developing, five Secure and four Greater Depth questions, plus one Super Challenge.
• All 23 differentiated answers together, followed by a separate challenge explanation.
• Three misconception checks with explained answers.
• An original six-mark exam-style question with answers and suggested marking points.
• Three exit questions, each immediately followed by its answer.

MODELLING AND PRACTICE
The paired examples cover rounding to the nearest ten, to a decimal place and to significant figures. Whole-class practice changes one feature at a time across groups: nearest tens, hundreds and integers; one, two and three decimal places; and significant figures at different scales. Pupils practise lower-inclusive, upper-exclusive intervals for positive values.

DIFFERENTIATION WITH DEPTH
Developing consolidates writing intervals across rounding accuracies. Secure asks pupils to recover rounded values and accuracy from intervals, identify possible exact values, convert bounds from kilograms to grams and count possible integers. Greater Depth explores why an upper bound is not a greatest possible value, restrictions to multiples of 0.01, whether two rounded reports can describe the same value, and counterexamples to claims about rounding.

ONE SUPER CHALLENGE
Pupils compare rounding an exact value directly with rounding an already rounded value. They find every value for which the two methods give different answers, state both results and justify the endpoints.

CHECK UNDERSTANDING
Misconceptions address interval width, excluded upper endpoints and the effect of stated accuracy. The exam-style task combines a capacity interval, conversion to millilitres and possible whole-number measurements. Exit checks revisit bounds, endpoint inclusion and reversing an interval to identify a rounded value.

PRINT FREE AND PRACTICAL
Project the slides while pupils answer in exercise books or on mini whiteboards. No printed worksheets are required. The whole class can work from the differentiated page at once, with the Super Challenge clearly separated. Text and diagrams remain editable.

Year 10 Unit 19, U657. Original questions from Beyond Printables.