Rich tasks
Tamati’s fishing trip
- Addition squares
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1. Tamati’s fishing trip
- This activity asks students to create 3-digit numbers and subtract 2-digit numbers from them.
2. Addition squares
- There are two addition squares for students to solve in this task. Students are asked to discover whether there is more than one way to solve them. An example is given to show students how to complete a square.
Adding using place value partitioning page 68
- Solve 2- and 3-digit addition problems using place value partitioning.
- Explain and record the addition strategy using place value materials, equations or number lines.
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Teacher notes
- Students sometimes have difficulty aligning place value when an equation has a 3-digit and a 2-digit number. Making the number using place value materials or identifying each place by writing H, T, O above each digit for a time can be helpful.
- Students also need to develop the habit of checking their answers to ensure they make sense. It is helpful to ask students before they solve a problem if they think the answer will be more than … or less than … and how they know this.
- Encourage students to make their thinking visible by writing, drawing, explaining or showing their strategy to others using appropriate place value materials. Working in groups of three with one student explaining, one student modelling with materials, and one student recording the strategy, is an effective way of ensuring that each student in the group is engaged and understands the strategy. Students can take turns in each role.
- The example on page 5 introduces rolling over the ten when adding numbers. Working with materials such as place value blocks will help to cement the understanding of what happens when the total number of ones is greater than ten.
Subtracting using place value partitioning page 72
- Solve 2- and 3-digit subtraction problems using place value partitioning.
- Explain and record the strategy using place value materials, equations or number lines.
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Teacher notes
- Working with place value materials initially is helpful alongside recording with an equation and/or number line.
- Some students may have difficultly aligning place value when adding or subtracting equations with different numbers of digits (e.g. 653-21). Making these numbers with place value materials or writing H T O above each digit for a time may be helpful.
Adding and subtracting using place value partitioning page 74
- Solve 2- and 3-digit addition and subtraction problems using place value partitioning.
- Explain and record the strategy using place value materials, equations or number lines.
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Teacher notes
- For word problems, students need to ascertain whether to add or subtract first before using place value partitioning to solve the problem.
- Encourage students to use an equation or number line to record their answers.
- Discourage students from partitioning both numbers as this can lead to mistakes later on when subtracting numbers where the ones digit in the number being subtracted is larger than the ones digit in the first number. Many students “swap” the numbers so that they can be subtracted.
