Small Skills Studio ・ Communicate
Read percentages, averages and charts with confidence.
Check units, baselines, averages, percentages and chart scales, then report numbers in three clear lines
- 12lectures
- 32minof lessons
- 2try-it tools
- 274lines of course audio
What changes with this skill
- Check whether units, periods and comparison baselines match
- Use counts and percentages, and the mean and median, for the right purpose
- Explain month-to-month, year-over-year and target comparisons, and percentage points
- Check chart axes and scales and separate correlation from causation
- Report numbers in three lines: fact, interpretation and open questions
What the course covers
Read numbers in a reliable order
You start with a simple headline such as "up ten percent" and ask: compared with what, in which unit and over which period? You then pair counts with percentages, choose between the mean and the median, compare month-to-month, year-over-year and against a target, and describe differences in percentage points. With charts, you check the axes and scales, separate correlation from causation and avoid strong claims from small samples.
Try it first
Compare the mean and the median
Weekly overtime hours for five people (fictional). Make one value much larger and watch the mean and the median.
Mean - h
Median - h
One extreme value moves the mean a lot, while the median barely changes.
How much did it grow?
+10%Percent vs percentage points
When a rate moves from 20% to 25%, “up 5 points” and “up 25%” describe the same change in different ways.
Difference (points)
Relative change (%)
Use “percentage points” for the gap between two rates and “%” for growth relative to the starting value.
All 12 lectures, chapter by chapter
Open a lecture to read its key points. Press “▶ A line from this lecture” to hear one sentence of the course audio.
Chapter 1
Prepare to read numbers
1.1Read a ten-percent increase
- Today's QuestionSales increased by 10 percent. / Does that alone mean the business is doing well?
- First, Look at the Original NumberPrevious Month: 1 Million Yen / This Month: 1.1 Million Yen / Increase Amount: 100 Thousand Yen
- The Same 10 Percent Means Different Amounts100 to 110: Increase of 10 / 1,000 to 1,100: Increase of 100
- Align the Comparison ConditionsPeriod, Number of Business Days, Scope / Are they compared under the same conditions?
- Small ExerciseLast Month: 200 Cases to This Month: 220 Cases / What is the increase count and rate?
- Make It a 3-Line ReportFact: 10% Increase Month-over-Month / Interpretation: Reason for Increase Undetermined / Confirmation: Business Days, Scope, Breakdown
- Takeaway for TodayOriginal Number, Comparison Target, Conditions / Ask These Three Things
1.2Align units and time periods
- Align units and time periodsAlign units and time periods / Work through a fictional example and exercise
- Confirming UnitsYen and ten thousand yen / Count of items and count of people
- Aligning PeriodsMonthly total / Per business day
- Calculation ProcedureDivide the total by the number of days / The unit also changes
- Confirming ScopeSame store? / Includes same products?
- Calculation Exercise200 items in 20 days / 225 items in 25 days
- Answer and VerificationFrom 10 items to 9 items / List total and average together
1.3Counts and percentages
- Counts and percentagesCounts and percentages / Work through a fictional example and exercise
- Scale and RatioHow many cases changed / What fraction of the original
- Two DepartmentsFrom 10 cases to 20 cases / From 1000 cases to 1100 cases
- Show the DenominatorAmong respondents / Among all subjects
- Do Not Add PercentagesGroups with different numbers of people / The total is calculated from the sum
- ExerciseFrom 5 cases to 10 cases / From 100 cases to 120 cases
- Answers and Reporting5 cases, 100% / 20 cases, 20%
Chapter 2
Averages and comparisons
2.1Mean and median
- Mean and medianMean and median / Work through a fictional example and exercise
- Calculating the MeanTotal divided by count / A value that balances the whole
- Calculating the MedianArrange in ascending order / Take the middle value
- Interpreting the DifferenceMean 6 minutes / Median 3 minutes
- Handling OutliersDo not automatically delete long values / Verify if it is an input error
- Exercise2, 2, 3, 3, 15 / Mean and Median
- Answer and VerificationMean 5 minutes / Median 3 minutes
2.2Compare with last month, last year and the target
- Compare with last month, last year and the targetCompare with last month, last year and the target / Work through a fictional example and exercise
- What is the Baseline?The immediately preceding month / The same month in the previous year
- Growth Rate and RatioMonth-over-Month 120% / 20% increase from last month
- Calculating Year-over-Year120 divided by 150 / Year-over-Year 80%
- Calculating Target RatioActual Results divided by Target / Represents achievement rate
- ExerciseActual 90, Previous Month 100 / Previous Year 80, Target 120
- Answers and Verification90%, 112.5% / Achievement Rate 75%
2.3Percentages and percentage points
- Percentages and percentage pointsPercentages and percentage points / Work through a fictional example and exercise
- Difference in ProportionsFrom 20% to 25% / The difference is 5 points
- Rate of Increase in ProportionsDivide the difference of 5 by the original 20 / Relatively, it is a 25% increase
- Verify with Actual Numbers20 people out of 100 / 25 people out of 100
- Correcting Ambiguous Expressions'Improved by 5%' is unclear / Show the before and after values
- ExerciseFrom 10% to 12% / Difference and Rate of Increase
- Answer and VerificationIncrease of 2 points / 20% increase
Chapter 3
Charts and causes
3.1Check graph axes and scales
- Check graph axes and scalesCheck graph axes and scales / Work through a fictional example and exercise
- Impressions Change Even with the Same Difference100 and 110 / Check the starting point of the axis
- Checking the Vertical AxisUnits and Scale Marks / Are the intervals equal?
- Checking the Horizontal AxisTime Intervals / Gaps in Periods
- Beware of Two AxesLines with Different Units / Closeness Does Not Prove Relationship
- ExerciseFrom 80 to 100 / What is the original increase rate?
- Answer and VerificationIncrease Rate is 25 Percent / Distinguish Between Appearance and Values
3.2Correlation and causation
- Correlation and causationCorrelation and causation / Work through a fictional example and exercise
- Moving SimultaneouslyIncreased Together / Not Necessarily the Cause
- Looking for Other ReasonsCommon Factors / Sequence of Time
- Considering Comparison GroupsGroup That Received Intervention / Group with Similar Conditions
- Wording of ReportsIncreased During the Same Period / Effect Undetermined
- ExerciseMistakes Decreased After Training / What Other Changes Occurred?
- Answer and VerificationWorkload and Difficulty / Recording Method
3.3Describe small samples carefully
- Describe small samples carefullyDescribe small samples carefully / Work through a fictional example and exercise
- Look at the Number of Cases2 out of 2 people / One hundred percent alone is insufficient
- The Weight of a Single CaseOne response changes 50 percentage points / With 100 people: 1 percentage point
- Look at How Data Was CollectedBias among respondents / Record the target and method
- Correcting Definitive StatementsEveryone wants it / Within the scope of respondents
- ExerciseThree out of four people agree / Make the report one sentence
- Answer and VerificationThree people agreed / Add verification of reasons and target
Chapter 4
Report in three lines
4.1Check changes in a spreadsheet
- Check changes in a spreadsheetCheck changes in a spreadsheet / Work through a fictional example and exercise
- Table LayoutColumn A: Items / Column B: Previous Month, Column C: Current Month
- Calculating the IncreaseD2: =C2-B2 / Result is 20
- Calculating the Increase RateE2: =(C2-B2)/B2 / Change format to Percentage
- When the Base is ZeroCannot divide by zero / Explained separately
- Exercise for VerificationFrom 200 to 180 / Also verify signs
- Answer and Save-20 items, -10% / Keep original data and formulas
4.2Separate facts from interpretation
- Separate facts from interpretationSeparate facts from interpretation / Work through a fictional example and exercise
- The Roles of Three LinesFact / Interpretation / Items to Confirm
- The Sentence for FactsFrom 200 cases to 220 cases / An increase of 20 cases, or 10 percent
- The Sentence for InterpretationsThe cause of the increase is undetermined / Whether it is good or bad depends on the content
- The Sentence for Items to ConfirmNumber of business days / Breakdown by content type
- ExerciseSales increased, so the advertisement was a success / Deconstructing assertions
- Answer and VerificationThe 10 percent increase is a fact / The effect of the advertisement is undetermined
4.3Write a report from fictional data
- Write a report from fictional dataWrite a report from fictional data / Work through a fictional example and exercise
- Conditions for the Final AssignmentLast month: 200 cases, 20 days / This month: 220 cases, 22 days
- Total Increase or DecreaseIncrease amount: 20 cases / Increase rate: 10 percent
- Per Business DayLast month: 10 inquiries per business day / This month: 10 inquiries per business day
- Creating the Three-Line ReportFacts should show both sides / Do not determine causes
- Complete It YourselfSave the table and three-line report / Verify calculations and wording
- Course SummaryReturn to the numbers / Increase questions necessary for decision
From the course audio
Lines from the course audio, one sentence at a time. Press to listen (in random order).
Udemy course
Read Workplace Numbers with Confidence
Check units, baselines, averages, percentages and chart scales, then report numbers in three clear lines
Who this course is for
- Beginners who want to interpret everyday workplace numbers without programming
- Professionals who feel unsure about percentages and comparisons
- Anyone who wants to present numbers without misleading others
- Learners who prefer fictional data and short exercises
Requirements
- Basic arithmetic
- A spreadsheet application for the calculation exercise (other lectures need no software)
Free preview lectures
- Read a ten-percent increase
- Align units and time periods
- Counts and percentages
Videos load from YouTube (youtube-nocookie.com) only when you press ▶.
Frequently asked questions
What is this course about?
This beginner course is for anyone who hesitates when percentages and comparisons come up in meetings. You will learn to check what a number is compared with, and to report it in three lines: the fact, the interpretation and what still needs checking. No programming is required.
How long is the course?
Twelve lectures, about 32 minutes in total. Each lecture moves through explanation, examples, a short exercise and a review.
Who is it for?
Beginners who want to interpret everyday workplace numbers without programming / Professionals who feel unsure about percentages and comparisons / Anyone who wants to present numbers without misleading others / Learners who prefer fictional data and short exercises
What do I need before starting?
Basic arithmetic / A spreadsheet application for the calculation exercise (other lectures need no software)
About the audio, illustrations and examples
The narration uses AI-generated voices, and the illustrations were created with generative AI. All examples, numbers and people are fictional; you never need to enter or submit real personal or workplace information.
