Common misconceptions › Class 8 › Maths › A Story of Numbers Class 8 Maths · Chapter 3 · NCERT (hegp103)
A Story of Numbers: common misconceptions
See the tempting mistake students make in A Story of Numbers, why it feels right at first glance, and a worked visual example that shows the right idea.
Worked visual “If your child says…” (8) Teach & practice The tempting mistake & worked visual Does an extra digit always make a number larger? Wrong
IX is larger than X because IX has two symbols.
Why it feels right. In our usual whole-number notation, more digits mean a larger number when there are no leading zeros.
Right
Roman numerals use a different rule. I before X subtracts one.
Worked example
IX X XI 9 10 11 On the number line, IX is before X and XI is after X. X is ten. IX is ten minus one, which is nine. XI is ten plus one, which is eleven. The position of I changes its effect. If your child says… (8 concept checks in this chapter)
As you work through A Story of Numbers , listen for these everyday misunderstandings and use the prompt alongside each one.
If your child says…
“Three ukasars mean two times two times two.”
Ask together How many beans do the three pairs contain altogether? What’s true Each repeated word adds another pair. If your child says…
“I always add every Roman symbol.”
Ask together Does IX place the one before the ten or after it? What’s true In IX, I before X signals subtraction. If your child says…
“Every Roman exchange needs ten copies.”
Ask together Did both exchanges in these lines need the same number of copies? What’s true The exchange size changes between Roman landmarks. If your child says…
“Moving an Egyptian symbol changes its value.”
Ask together Would moving the arch change what its shape means? What’s true Its shape determines its value, regardless of position. If your child says…
“Base five lets me write the digit 5.”
Ask together What larger group do five five-square strips make? What’s true Five groups must exchange for the next size, leaving each digit below five. If your child says…
“I just add the two groups.”
Ask together What does the 60s heading make the left wedge worth? What’s true The left group counts sixties when the right group counts ones. If your child says…
“The third Maya place must be four hundred.”
Ask together Does multiplying twenty by twenty reach the top row's value? What’s true These Maya calendar places reach 360 by multiplying twenty by eighteen. If your child says…
“I can leave an empty place out.”
Ask together After removing the coin, would writing just 1 show the note's value? What’s true Leaving out an empty place moves digits to its left into lower places. Use this chapter three ways Previous chapter Power Play Next chapter Quadrilaterals
In the app, your child answers a short check-in with confidence taps, and you see which of these misunderstandings showed up—and which ones are gone.
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