Cleo the time traveller is back at the mill during the 1850s to continue exploring and helping people with their maths problems. This time, she will be adding and subtracting 10s.
More resources for Autumn Block 2 Step 8.
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Discussion points for teachers
1. How many will I have altogether?
Discuss how many employees Mr Rothwell already has. Discuss how many more employees Mr Rothwell will have. Discuss how we can use the column addition to show this. Discuss which digit changes and why.
79 + 20 = 99
2. How many have fallen off my cart?
Discuss how many sacks the mill worker started with. Discuss how many he now has. Discuss how we can use column subtraction to work out the missing value.
65 – 30 = 35. 30 have fallen off the cart.
3. How many have we doffed altogether?
Discuss how many the first mill worker has doffed. Discuss how many the second mill worker has doffed. Discuss showing this in a column addition calculation. Discuss which digit changes and why.
45 + 40 = 85
4. Help Cleo to work out which combination of machines the young mill worker could deliver bobbins to.
Discuss how many bobbins the mill worker has in total. Discuss which combinations of machines reach the maximum number of bobbins available. Discuss which digit will not change, no matter which combination we choose and why. This question is open-ended for children to explore.
Various answers, for example: machine 1, machine 2, machine 3 ( 30 + 40 + 20 = 90)
Optional discussion points:
Will the ones digit ever change if we only add tens?
National Curriculum Objectives
Mathematics Year 2: (2C2a) Add and subtract numbers mentally, including: a two-digit number and tens
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