Diver Dan is exploring a sunken pirate ship. He is counting the different objects and creatures and solving puzzles to find the treasure. He needs help to find one more and one less.
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Discussion points for teachers
1.What might he find in the ship?
Discuss what things Dan might find on a sunken pirate ship. This question is open-ended for the children to explore.
2.How many shells has he collected?
Discuss how many shells he had collected. Discuss the meaning of 1 more. Discuss how many shells Dan has.
3.How many fish and seahorses can Dan see?
Discuss counting the fish and seahorses and recording the answers.
10 fish and 12 seahorses.
4.How many fish and seahorses would there be?
Discuss what happened and how that changes the number of fish and seahorses Dan can see now. Discuss using the answers from the previous question to find one more and one less than each number.
11 fish and 11 seahorses.
5.What is the code?
Discuss the meaning of 1 more and 1 less. Discuss which number is one less than 20 but one more than 18.
6.Which gems could complete the statement and open the secret compartment?
Discuss the meaning of ‘1 less than’ a number. Discuss if the number in the first space needs to be greater than or less than the number in the second space. Discuss using the gems to make 2 digits numbers that will complete the statement. This question is open-ended for the children to explore.
Various answers, for example: 12 is 1 less than 13; 13 is 1 less than 14.
Optional discussion points:
When might you use 1 more or 1 less?
National Curriculum Objectives
Mathematics Year 1: (1N1a) Count to 20, forwards and backwards, beginning with 0 or 1, or from any given number
Mathematics Year 1: (1N2a) Count, read and write numbers to 100 in numerals
Mathematics Year 1: (1N2b) Given a number, identify one more and one less
Mathematics Year 1: (1N4) Identify and represent numbers using objects and pictorial representations including the number line, and use the language of: equal to, more than, less than (fewer), most, least
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