# Adding and subtracting with counters or hands

Achievement Objectives
NA1-1: Use a range of counting, grouping, and equal-sharing strategies with whole numbers and fractions.
NA1-1: Use a range of counting, grouping, and equal-sharing strategies with whole numbers and fractions.
Specific Learning Outcomes

Solve addition problems to 20 by joining sets and counting all the objects.

Description of Mathematics

Number Framework Stage 1

Required Resource Materials
counters
Activity

#### Using materials (result unknown)

Problem: Ioane has four bottles of drink in the cupboard, and he buys three more bottles for his birthday party. How many bottles of drink does Ioane have now?

Discuss and record 4 + 3 = ? as a word problem on the board or in the modelling book.
Have the students solve the problem using counters.
If you are using pre-printed tens frames, provide a tens frame printed with four dots.
Ask the students to point to where three more counters would go.
It is important that students complete a column of five and then add two more in the other column.
Discuss the answer and record the solution to 4 + 3 on the board or in the modelling book.

Examples: Word problems and recording for: 3 + 5, 2 + 5, 6 + 2, 2 + 8, 4 + 4, 7 + 2 …

#### Using materials (result unknown)

Problem: Hohepa puts eight boiled eggs on the breakfast table. Moana and Hinewai eat one egg each. How many eggs are left?

Discuss and record 8 – 2 = ? as a word problem on the board or in the modelling book.
Have the students solve the problem using physical materials like counters or pre-printed tens frames.
If using pre-printed tens frames, it is important that students model the eight by completing a column of five and a column of three.
Discuss the answer and record the solution to 8 – 2 on the board or in the modelling book.

Examples: Word problems and recording for: 6 – 3, 10 – 3, 7 – 6, 9 – 1, 6 – 5 …

#### Using imaging (result unknown)

Problem: Ranjit has five jellybeans, and he gets three more jellybeans from a friend. How many jellybeans does Ranjit have now?

Discuss and record 5 + 3 = ? as a word problem on the board or in the modelling book.
Out of the students’ sight, build five on an empty tens frame.
Show the students the tens frame and ask them to describe how you built it.
Drawing pictures in the air may help.
Add three, out of the students’ sight, and ask them to explain how you built it.
Ask how many counters there are altogether.
If necessary, fold back to “Using materials” by showing the students the hidden counters.
Discuss the answer and record the solution to 5 + 3 on the board or in the modelling book.

Examples: Word problems and recording for: 4 + 5, 10 – 4, 6 – 5, 5 + 2, 10 – 8 ...

#### Using imaging (change unknown)

Problem: Carol has eight eggs in the cupboard. She uses some eggs to make a cake, and then there are only five eggs left in the cupboard. How many eggs did Carol use for the cake?

Discuss and record 8 – ? = 5 as a word problem on the board or in the modelling book.
Have the students put both hands behind their backs and model the eight, then show how they would remove five to work out how many eggs were used.
If necessary, fold back to “Using materials” (the students bring their hands out in front of them) to solve the problem.
Discuss the answer and record the solution to 8 – ? = 5 on the board or in the modelling book.

Examples: Word problems and recording for: 9 – ? = 4, 2 + ? = 5, 8 – ? = 5, 2 – ?  = 1, 3 + ? = 8 …

#### Using imaging (change unknown)

Problem: Ana has seven dollars. She spends some money on an ice cream. Now she has four dollars. How much did Ana spend on her ice cream?

Discuss and record 7 – ? = 4 as a word problem on the board or in the modelling book.
Hide a preprinted tens frame with seven dots and ask the students to image the tens frame and to talk about the model they have imaged.
Then have the students image the removing of three dots.
If necessary, fold back to “Using materials” by showing seven dots and shielding three of the dots.
Discuss the answer and record the solution to 7 – ? = 4 on the board or in the modelling book.

Examples: Word problems and recording for: 3 + ? = 7, 8 – ? = 6, 4 + ? = 9, 8 – ? = 6, ? + 4 = 8 …