Mathematics Online Interview and Fractions and Decimal Online Interview

Mathematics Online Interview

The Mathematics Online Interview (MOI) was developed as part of the Early Numeracy Research Project (EMRP). For more information on the EMRP, please see: Early Numeracy Research Project Summary (pdf - 646.56kb).

The MOI is an online tool for assessing the mathematical knowledge of students in the early years of schooling and of 'at risk' students in the middle and upper primary levels.

The interview is one-to-one between a teacher and student. The testing is in relation to growth points, which can be described as key "stepping stones" along paths to mathematical understanding. Refer to the growth points while conducting the interview.

Teachers record each student's responses directly into the online system. This data is used to generate reports and provide an overview of student achievement and diagnostic information to inform program planning and teacher practice.

Access the Mathematics Online Interview
Via the Insight Assessment Platform

Please note, schools should keep CASES21 teacher, class and student data up to date for students, to ensure the data is accurate on the insight platform, allowing for efficient delivery of MOI assessments.

Useful resources: information guide, reference guide and equipment checklist

MOI Information Guide

  • For information on Mathematics Online Interview (MOI), its structure and alignment to the Framework for Improving Student Outcomes (FISO 2.0) download the MOI Information Guide( docx - 365.73kb)

MOI Reference Guide

MOI Equipment Checklist

Mapping the interview to the Victorian Curriculum

This document links tasks from the Mathematics Online Interview to the Level, Strand, Code, Content Descriptions as well as the Elaborations of the Victorian Curriculum F-10: Mathematics.

Please note the following document has been updated to reflect a more accurate mapping to the Victorian Curriculum F-10.  

Fractions and Decimals Online Interview

The Fractions and Decimals Online interview (FDOI) is an online tool for assessing student mathematical understandings and strategies of fractions, decimals, ratio and percentage. FDOI is intended for students in years 5 to 8 but is also valuable for assessing high achieving students in year 4, or at-risk students in year 10.

The interview is one-to-one between a teacher and student. Teachers record each student's responses directly into the online system. The interview provides collated data that can be compared within schools to understand student achievement and monitor progress.

Access the Fractions and Decimals Online Interview
Via the Insight Assessment Platform

Useful resources: reference guide, equipment checklist and online interview classroom activities guides

FDOI Reference Guide

FDOI Equipment Checklist

FDOI Online Interview Classroom Activities

For a range of classroom tasks linked to the Fractions and Decimals Online Interview download the FDOI Classroom Activities (pdf - 1 (pdf - 1.5mb)

Mapping the Interview to the Victorian Curriculum

This document links each task from the Fractions and Decimals Online Interview (FDOI) to the overarching big idea to which it relates.

The task and the big idea have been mapped to the content description and elaborations from the Victorian Curriculum F-10: Mathematics which provides the best match.

Please note the following document has been updated to reflect a more accurate mapping to the Victorian Curriculum F-10.  

Mapping the fractions and decimals online interview to the Victorian Curriculum F-10 (docx - 475kb)

Big ideas linked to the Fractions and Decimal Online Interview

FDOI are linked to 'big ideas' which are  the knowledge, skills and behaviours students who have connected understandings of fraction ideas may possess. These capabilities have been divided these into overall ideas and those that relate to particular constructs of rational number.

As fractions is a major focus with the Interview, there is some occasions where only fractions is referred, while in other cases, the broader term rational number is used (to include fractions, decimals, percentages, etc.).

The numbers in the parentheses refers to the corresponding questions in the interview.

Overall ideas

  • Articulates rational number thinking using appropriate language [Questions 1-20]
  • Forms and manipulates a variety of physical and mental models (areas and regions, sets, number lines, ratio tables, etc), in continuous and discrete situations [Questions 1-20]
  • Understands the subconstructs of rational number (part/whole [Questions 1-4, 6], division [Question 6], measure [Questions 8-11], ratio, and operator [Question 4]) as well as their interrelationships
  • Understands that rational numbers are largely about relationships [Questions 1-3, 6, 7, 9, 12-15, 20]
  • Thinking multiplicatively rather than additively when appropriate (relative Vs absolute thinking) [Question 17]
  • Understands that fractions are equal shares that are not necessarily congruent and that the subdivision of the whole must be exhaustive [Question 1]
  • Recognises that a given fraction (continuous/discrete) of a may not be the same size as that fraction of b [Question 19]
  • Moves from the whole to a given part, from the part to the whole and from the part to the part flexibly [Questions 2, 3, 6, 7]
  • Understands that if a is a certain fraction of b, we can determine what fraction b is of a, through the reciprocal relationship
Connecting concepts with symbols/equivalences 
  • Understands the meaning attached to each part of a fraction (e.g., the denominator shows what 'denomination' is being counted, the numerator 'enumerates' how many of these parts) [Questions 9, 12, 14, 18]
  • Understands that fractions (including whole numbers, mixed numbers and improper fractions) are entities that can be counted (e.g. 4/5 represents four things called "fifths") and can recognise and use counting patterns and equivalences [Questions 3, 5, 9, 12, 14]
  • Uses appropriate symbols to represent rational numbers (e.g. fractions, decimals and percentages) and can flexibly move between these as appropriate
Fractions as a number

  • Understands and operates with the 'density' of rational numbers (meaning that between any two rational numbers there is an infinite number of rational numbers), relating them appropriately to whole numbers [Question 11]
  • Can identify a rational number on a number line with consideration to the calibrations and the intervals specified [Question 10]

Fractions as a division

  • Recognises a/b as a divided by b [Questions 6, 16]
  • Can solve whole number division problems understanding the significance of the size of the quotient (e.g. 4 ÷ 5 will result in an answer less than one) and/or treating remainders appropriately [Questions 6, 17]
  • Has appropriate strategies in sharing-type problems [Question6]

Relative size/benchmarking

  • Readily compares and orders rational numbers, using efficient and understood strategies [Questions 5, 9-11, 13, 15]
  • Relates a given rational number to key benchmarks (e.g. 0, ½, 1), using place value as appropriate [Questions 5, 8-11, 13, 15]
  • Understands the inverse relationship between the denominator and the size of the parts [Questions 7, 9]

Operators and operations

  • Combines and partitions rational numbers using appropriate physical or mental tools, renaming as appropriate [Questions 4, 6, 10-12, 14, 16, 18]
  • Estimates the answer appropriately in a rational number calculation [Questions 8, 16, 17, 19, 20]
  • Can nominate a problem situation to which a particular rational number operation might apply, and conversely can represent a relevant rational number operation given the problem situation [Questions 17, 19, 20]

Strategies and Misconceptions

This information will assist teachers in developing their understanding in relation to the types of strategies that students use to demonstrate their fraction understanding, for example residual thinking, and support teachers identify misconceptions in student knowledge and understanding.


Correct benchmarking is evidence that a student understands the relative size of fractions. It is also useful for comparing decimals. When benchmarking, a student will compare a fraction to another well-known fraction, usually a half, or to a whole number such as zero or one. For example, when comparing 5/8 and 3/7; 5/8 is greater than a half, and 3/7 is less than a half, therefore 5/8 is bigger.             

Residual thinking

The term residual refers to the amount which is required to build up to the whole. For example, 5/6 has a residual of 1/6. This thinking is useful for comparing the size of fractions such as 5/6 and 7/8. 5/6 has a residual of 1/6 and 7/8 has a residual of 1/8. Therefore 7/8 is a larger fraction because it has the smaller residual – the smaller amount to make the whole. Sometimes, however, residual thinking alone is not an efficient strategy. When comparing 3/7 & 5/8, measuring up the residuals of 4/7 & 3/8 is not a helpful strategy as you are left with two residuals that are no easier to compare than the original pair. In this case, the residuals then need to be benchmarked to 1/2 and 1 to prove which is larger. If students use residual thinking alone with this pair, it should be classified as an unsatisfactory explanation.                 

Residual thinking with equivalence

In order to use residual thinking effectively, creating an equivalent residual sometimes makes the justification clearer. For example, when comparing 3/4 and 7/9 a student may state that 3/4 has a residual of 1/4 or 2/8. Therefore, the residual for 7/9 (2/9) is smaller than the residual for 3/4 (2/8). The fraction with the smaller residual is the larger fraction.           

Residual thinking with some other proof

Sometimes residual thinking alone is not the most appropriate strategy. For example, if a student uses residual thinking alone to compare 3/4 and 7/9, they must then convince the interviewer that they can justify which of the residuals is bigger (1/4 or 2/9). An example of residual with proof might be, “I know one quarter of nine is more than 2 because 2 is a quarter of eight, so 2/9 must be less than 1/4 therefore 7/9 is the bigger fraction”. Please note: an explanation of residual thinking without proof, should be recorded as “other (unsatisfactory explanation for either a correct or incorrect solution)”.                

Gap thinking

This strategy is a form of whole number thinking, where the student compares the whole number difference between the numerator and denominator. For example, 5/6 and 7/8 both have a difference of “one” between the numerator and denominator. A student using “gap thinking” might claim therefore that these fractions are the same size. When comparing 3/4 and 7/9, a student using gap thinking would choose 3/4 as larger because it has a smaller “gap”, thereby choosing incorrectly. There are some instances where “gap thinking” will lead students to a correct choice. For example, comparing 3/8 & 7/8. This is an inappropriate strategy for comparing the size of fractions.                 

“Higher” or “larger” numbers

With this strategy, fractions are deemed to be bigger if they contain larger digits. For example, when comparing 4/7 and 4/5 students may incorrectly claim that 4/7 is larger because it has a “larger number”. Also, in comparing 2/4 and 4/8, a student would choose 4/8 as it has “higher numbers”. Sometimes students will directly compare the numerators or denominators and conclude a larger digit at the top or bottom of a fraction means that it is a larger fraction. This is an inappropriate strategy for comparing the size of fractions.                

Other (satisfactory explanation with a correct solution)

There are very few correct solutions with appropriate strategies that do not already fall into the provided categories, but it is possible for this to occur. For example: a student may be able to mentally convert a fraction to a decimal and then compare or use some other mathematically correct strategy. This option is only for correct solution and appropriate explanation.                

Other (unsatisfactory explanation with either a correct or incorrect explanation)

There are many explanations (too numerous to mention) that may fall into this category. It is a “catch-all” for any strategy that cannot be placed in the other categories. Typically, it will include any explanation that is mathematically incorrect, partially correct or vague. Sometimes students relate fractions to an image of an area model. Their justification might be “7/9 is larger than 3/4 because if I imagined a picture of them, 7/9 would look more”. This reasoning is not evidence of understanding the size of the fractions. In a situation where the student provides a partially correct or vague explanation, it is appropriate to ask for further information in a non-leading way. For example, “can you tell me more about how you know? So you think it seems larger, but how can you be sure?”

Further support: