Math · Stage 2
Reason about chimes and the gaps between them (intervals, off-by-one)
A clock that chimes 6 times leaves only 5 silences in between — the gaps are always one fewer than the chimes.
✦ Math📘 Stage 2 · S2⏱ ~10 min🧒 Ages 6–7★ Free to start
I can reason about chimes and the gaps between them: the number of gaps (intervals) is one fewer than the number of chimes (off-by-one).
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Kavi Counts the Clock Tower 🔔
The old clock tower starts to chime! Kavi counts the bongs: DONG… DONG… DONG — three chimes for 3 o'clock! Then Kavi listens to the silences between them: there are only two gaps, one after the first bong and one after the second. "The last chime has no gap after it," hoots Kavi. "So the gaps are always one fewer than the chimes!"
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What your child will learn
1Three o'clock — three chimesAt 3 o'clock the clock chimes 3 times: DONG · DONG · DONG. Say each bong out loud and clap the silence between each pair of bongs — between bong 1&2, and between bong 2&3.
2Line up the chimes, count the spacesHere are 6 chimes for 6 o'clock, as 6 beats: 1, 2, 3, 4, 5, 6. Now point to each gap between two neighbouring chimes — between 1&2, 2&3, 3&4, 4&5, 5&6.
3The gaps are the hopsPut the chimes as marks on a line, 0 to 5 — that is 6 marks, like 6 chimes. Tap Hop and watch each hop jump the gap between two marks. The hops are the silences between the chimes.
4The rule as a number bondFlip it into a number bond: the gaps plus 1 make the chimes. For 5 chimes: 4 gaps + 1 = 5 chimes. So gaps = chimes − 1.
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A peek inside
The clock tower chimes 3 times for 3 o'clock. How many gaps of silence are between the chimes?
count chimes: 1 2 3 · gaps sit between pairs: (1-2)(2-3) = 2 · gaps = chimes − 1 = 3 − 1
Try this at home: A clock chimes 5 times for 5 o'clock. How many gaps of silence are between the chimes?
Part of Math · Stage 2 · S2 on KAVI Academy — a secular, whole-child learning platform for ages 5–12.