Capabilities Project.
MT3.5 – Addition 2 digits
Name
Date
Class
Part A. Place your answer the box:
5 + 4 =
7 + 3 =
8 + 5 =
16 + 5 =
5 - 4 =
7 - 3 =
18 - 9 =
21 - 5 =
Part B: Place your answer in below the line.
12
+19
Part C:
72
+49
32
+65
42
- 16
47 + 16 = ?
Part D: Show how you can do a 2 digit subtraction.
132
+ 15
(show your work)
112
+ 15
Capabilities Project.
MT3.5 –Addition 2 digits regrouping Assessment Criteria:
Source:
Discussion:
Naplan 2012 Y3 NC Q10.
(Queensland Studies Authority. www.qsa.qld.edu.au)
The development of the standard algorithm should follow the development of mental computation and informal
approaches and be introduced as an extension of students’ existing strategies to enable them to deal with larger
numbers easily. It is only by having students explain their strategies that teachers can really know how students
are reasoning their way through a problem.
Curriculum References:
Statements of Learning.
Y3
Students have the opportunity to choose between mental and written methods, including the students’ own written
recordings, when adding and subtracting one- and two-digit numbers and make estimates to check these
calculations.
• choose between mental and written methods, including the students’ own written recordings, when
adding and subtracting one- and two-digit numbers and make estimates to check these calculations
Australian Curriculum.
L3
Recall addition facts for single-digit numbers and related subtraction facts to develop increasingly efficient mental
strategies for computation. (ACMNA055)
• recognising that certain single-digit number combinations always result in the same answer for addition and
subtraction, and using this knowledge for addition and subtraction of larger numbers
AusVels.
L3.5
 count and order numbers to and from tens of thousands, and use addition and subtraction facts to develop
efficient mental strategies for computation.
Proficiencies.
L3
 recognise the connection between addition and subtraction.
Relationship to Multiplicative Thinking.
Students recognise that a total in any one column can only be one digit, the digit 9 being the maximum. Beyond
that, a new column to hold the multiples of the previous column are needed.
Capabilities Project.
For subtraction, when the focus column has too few to subtract from, a multiple from the adjacent left column must
be regrouped. A MULTIPLE (10 of that place value) is used in the regrouping.