Finding durations that cross hour boundaries or span multiple hours (e.g., 10:45 to 13:20), including counting on through noon/midnight.
Where your child meets this in real life: Working out journey times, shift lengths at work, or how long until an event
SEAGReady breaks calculate complex time durations into 3 steps, taught in order so each skill builds on the last.
Calculate duration when start and end times cross exactly one hour boundary (e.g., 10:45 to 11:20)
Calculate duration when start and end times span two or more complete hours (e.g., 10:45 to 13:20)
Calculate duration when times cross noon (am to pm) or midnight (pm to am), including in 24-hour format
Three free sample questions from our calculate complex time durations course. Every question comes with a full explanation, and hints that guide without giving the answer away.
The clocks show when Sean's football practice starts and finishes. How long is his football practice?
The displays show when Aaron's train leaves and arrives. How long was his train journey?
A ferry leaves at 10:50 am and arrives at 1:35 pm. How long is the crossing?
This is the exact interactive worked example your child sees in SEAGReady. Step through it and watch the method build up.
Olivia's swimming lesson starts at 10:45 and finishes at 11:20.
How long is her swimming lesson?
10:45 to 11:20
Start at 10:45. How many minutes to reach 11:00?
Step 1 of 4
Olivia's swimming lesson starts at 10:45 and finishes at 11:20.
How long is her swimming lesson?
Olivia's swimming lesson lasts 35 minutes.
The key insight: Bridge through the hour: count to :00, then add the rest!
Common mix-up: 11:20 − 10:45 = 0:75 = 75 minutes. You cannot subtract times like regular numbers. 20 − 45 gives a negative, which means you need to bridge through the hour.
These are the misconceptions we see most often in calculate complex time durations, including the ones our practice questions are specifically designed to catch.
Struggling with calculate complex time durations? The real gap is often in one of these earlier topics.
SEAGReady finds the exact step where your child gets stuck, teaches it with worked examples like the one above, and brings it back for review so it sticks.
Free to start · no card needed