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# Adding and Subtracting with One Hand

Keywords:
Achievement Objectives:

Achievement Objective: NA1-1: Use a range of counting, grouping, and equal-sharing strategies with whole numbers and fractions.
AO elaboration and other teaching resources
Achievement Objective: NA1-3: Know groupings with five, within ten, and with ten.
AO elaboration and other teaching resources

Specific Learning Outcomes:
Solve subtraction problems from 20 by separating sets and counting all the objects.
Instantly recognise patterns to 5, including finger patterns.
Description of mathematics:

Number Framework Stage 1 and 3

Activity:

#### Using materials (result unknown)

Problem: Jayanti has three carrots, and she buys two more carrots. How many carrots does Jayanti have now?

Discuss and record 3 + 2 = ? as a word problem on the board or in the modelling book.
The students model three fingers, and then two more fingers, on the same hand.
Without counting to solve the problem, the students need to recognise that three fingers and two fingers equal five fingers.
Record the solution to 3 + 2 on the board or in the modelling book.

Examples: Word problems and recording for: 1 + 4, 3 + 1, 5 – 2, 4 – 3, 2 + 3, 4 – 1 …

#### Using imaging (result unknown)

Problem: There are four carrots in the fridge and one carrot on the bench. How many carrots are there altogether?

Discuss and record 4 + 1 = ? as a word problem on the board or in the modelling book.
Have the students solve the problem by imaging the numbers.
If necessary, have the students fold back to “Using materials” by modelling four fingers and one more finger on the same hand.
Record the solution to 4 + 1 = ? on the board or in the modelling book.

Examples: Word problems and recording for: 1 + 4, 3 + 1, 5 – 1, 4 – 3, 2 + 3, 5 – 2 …

#### Using materials (change unknown)

Problem: When Pippa goes to sleep, she has three Easter eggs in her bedroom. While she is asleep, her mother gives her some more Easter eggs. She wakes up in the morning to find that she has five Easter eggs. How many eggs did her mother give Pippa?

Discuss and record 3 + ? = 5 as a word problem on the board or in the modelling book.
Encourage the students to act out the problem for themselves using counters.
Record the solution to 3 + ? = 5 on the board or in the modelling book.

Examples: Word problems and recording for: 1 + ? = 4, 4 + ? = 5, 5 – ? = 2, 4 – ? = 3 …

#### Using imaging (change unknown)

Problem: Pippa’s mother has five Easter eggs. She gives some of them to Pippa. Pippa’s mother now only has two eggs left. How many did she give to Pippa?

Discuss and record 5 – ? = 2 as a word problem on the board or in the modelling book.
The students each put a hand behind their back and think about the missing number.
If necessary, have the students fold back to “Using materials” by putting five counters in front of them and solving the problem.
Record the solution to 5 – ? = 2 on the board or in the modelling book.

Examples: Word problems and recording for: 1 + ? = 4, 5 – ? = 0, 4 – ? = 2, 3 + ? = 5 …