A map full of squares

Liri’s star map had grown. What used to be a small section now showed hundreds of squares in every direction.

Liri: “My memory says: 3 hundreds and 5 ones to get to this point. But I don’t know how to write that as one number.”
Erklärus: “Then you need a third place. After the tens now come the hundreds.”

📦 From the tens rod to the hundreds flat

Just as ten ones cubes make a tens rod, ten tens rods now make a whole hundreds flat.

1 hundreds flat = 100 (10 × 10)

10 rows of 10 squares each – that is 10 tens rods side by side, making 100 altogether at a glance.

🎯 The place value chart – the same counter, a different value

In the place value chart it is not the counter itself that matters, but where it sits. Three counters under H mean 300 – the same three counters under O would only mean 3!

H
T
O

3 hundreds, 0 tens, 5 ones = 305

Erklärus: “Watch out for the zero! There isn’t a single counter in the tens column – but that doesn’t mean we leave the column out. We write a 0 so that all the other digits stay in the right place.”

✍️ Number dictation

Erklärus says a number – you write it down. Watch out for the zero as a placeholder!

Erklärus: “I say: 3 hundreds, 5 ones.”

⚖️ Comparing numbers up to 1,000

The ISS flies at a height of about 400 kilometres above the Earth. The Saturn V rocket was 111 metres tall. Which sign fits?

400
111

🎯 Rounding to the nearest ten or hundred

A telescope picture shows exactly 386 stars. About how many is that?

Rounded to the nearest ten:
Rounded to the nearest hundred:
🌌 Numbers up to 1,000 in the universe

The space station ISS flies at a height of about 400 kilometres above the Earth.
The Moon rocket Saturn V was 111 metres tall.
More than 500 meteorite impact craters have been found on Earth so far.

❌ Common mistake

When a place is “empty”, it is often simply left out: “3 hundreds, 5 ones” then wrongly becomes 35 instead of 305.

Tip: always go through all three columns (H, T, O) in your head – an empty column gets a 0, it never just disappears!

🎯 Exercise 1 – Place value chart
In the place value chart there are: 2 counters under H, 4 under T, none under O. Which number is that?
✍️ Exercise 2 – Number dictation
Erklärus says: “7 hundreds, 0 tens, 9 ones.” Which number does he mean?
🌠 Exercise 3 – A jump on the number line
Liri is at 450 on the number line and makes a jump of 100 forwards. Where does she land?

A more precise point

Liri wrote 305 on her map – this time without hesitating. The zero in the right place made the difference between a point nearby and a point far away.

Liri: “One single missing zero, and I would have ended up in the wrong place.”
Erklärus: “That is exactly why the place value chart is so important. Every place counts – even the empty ones.”
“Numbers up to 1,000: H | T | O. Ten tens rods = one hundreds flat. An empty place gets a zero, it never disappears. Rounding: look at the nearest ten or hundred.”
What you learned today
3 H + 0 T + 5 O = 305
Place value chart: H | T | O  ·  Empty place = zero, never leave it out
🌟

Chapter 13 mastered!

Liri can now read, write and compare numbers up to 1,000 – including zeros as placeholders.

Erklärus’s notebook – page 13:
“Numbers up to 1,000: place value chart H | T | O. Ten tens = one hundred. An empty column always gets a zero. Rounding means: look at the nearest multiple of ten or a hundred and see which is closer.”
← Back to overview 13 – Numbers up to 1,000