Word Problems
Word problems are where everything in this chapter comes together — unit conversion, a.m./p.m. handling, calendar counting and elapsed time, dressed up in a real situation. The skill is translation: read the situation, decide which of the three elapsed-time questions it is (find the end, find the start, or find the duration), pick the right conversion factors, and watch the boundaries at noon, midnight and the ends of months. A few habits keep candidates out of trouble. When a span crosses 12 noon or 12 midnight, break it at the boundary and add the pieces rather than subtracting straight through. When counting days across two dates, decide first whether the count is inclusive (both end dates counted) or exclusive — a camp 'from 15 May to 10 June, both days included' is (31 - 15 + 1) + 10 = 17 + 10 = 27 days, and forgetting the +1 is the classic slip. When the months differ, count the days left in the first month, add the whole months in between, then add the days into the last month, remembering the real length of each month rather than assuming 30. And always reach for counting-up on duration questions to dodge the base-60 borrowing that creates wrong answers like 4:75 or 2:35.
✅ Solved examples
✏️ Practice — try these, take hints as needed
📝 Topic test — 8 questions
Auto-graded with full solutions; saved to your dashboard. Use the calculator and formula sheet (top-right) any time.
Key Concepts — Quick Reference
Units of time (the ladder you must know cold)
| Seconds to minute | 60 seconds = 1 minute |
|---|---|
| Minutes to hour | 60 minutes = 1 hour (so 1 hour = 3600 seconds) |
| Hours to day | 24 hours = 1 day (= 1440 minutes = 86400 seconds) |
| Days to week | 7 days = 1 week; 14 days = 1 fortnight |
| Months & years | 12 months = 1 year; 10 yrs = decade; 100 yrs = century |
Clock angles & the leap-year rule
| Minute hand | sweeps 360 deg in 60 min = 6 deg per minute |
|---|---|
| Hour hand | sweeps 360 deg in 12 hr = 30 deg per hour = 0.5 deg per minute |
| One number gap | 5 minutes = 30 deg between two clock numbers |
| Common vs leap year | 365 days = 52 weeks + 1 day; 366 days = 52 weeks + 2 days |
| Leap-year test | divisible by 4; but a century (00) year only if divisible by 400 |