Longer and Shorter

Which takes longer? What comes first? And which one is the clock?

Book Compare and measure K.MD.A.1K.MD.A.2 ALPACA · Early number

For grown-ups

How long: 10 to 15 minutes is plenty. Short and frequent beats long and occasional — the early-numeracy trials with the largest effects ran eight weeks or less.
When they get one wrong: the page shows the working. Read it together rather than moving straight on. Feedback that explains is worth several times more than feedback that only marks right or wrong, and that gap is wider in maths than in any other subject.
Not timed: thinking time is the point of a book. Let silences run.
Print it too: doing the same problems on paper a few days later is worth more than doing twice as many today.

What this practises

Comparing how long things take, putting a day in order, and knowing a clock when you see one.

Said plainly: there is NO Common Core time standard at Kindergarten, and no Illustrative Mathematics unit either. This activity is mapped to K.MD.A.1 and K.MD.A.2 — describing and directly comparing a measurable attribute — with duration as the attribute, which is a defensible reading of a standard whose own examples are length and weight, and not a claim that CCSS asks for time at K. It is here because several state frameworks do place clock familiarity at K, because grade 1 assumes it, and because comparing durations is genuine K.MD work. No item asks a Kindergarten child to read a clock; that is 1.MD.B.3 and Clocks and Time does it.

The underlying idea: Time is a measurable attribute before it is a number. A child who can say that sleeping takes longer than a sneeze has the idea that durations can be compared, which is what reading a clock will later put numbers to. Comparing before measuring is the order K.MD uses for length, and it is the order used here.
Where this sits in Illustrative Mathematics: Kindergarten Unit 1: Math in Our World
Sources: Illustrative Mathematics / Kendall Hunt (2024) · Illustrative Mathematics (2024) all references →

Related measured skill: ALPACA · Early number. What this means