7 reasons the Do Now takes too long... and what you can do about it

Strategies to improve an all too important phase of a lesson

Apr 01, 2025

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The page on my Tips for Teachers website with the most views is the one dedicated to the start of the lesson - the Do Now. This is not surprising. Even though the Do Now is - or should be - short, the fact that it is the first phase of a lesson means it sets the tone for all that follows. Get your Do Now right, and your students transition into the main body of the lesson feeling focused and successful. Get it wrong, and you might spend the next 50 minutes frantically picking up the pieces.

I share many ideas on my Do Now page to help make this lesson phase as impactful as possible. Here, I want to address a specific issue with many of the Do Nows I see during my weekly visits to maths classrooms around the UK: the Do Now takes too long.

Ask most teachers how long the Do Now should last, and they will say around 10 minutes. I regularly witness Do Nows that last between 20 and 30 minutes. The result is always the same: the rest of the lesson gets squished into the time that remains, leading to rushed I Dos, curtailed consolidation, and no opportunities for problem-solving.

Based on the 1000s of Do Nows I have seen over the years, here are the top 7 reasons it takes longer than teachers hope… and what you can do about it.

Reason 1: Students arrive late to lessons, so the teacher has to wait for these students to finish

Solution: Lateness to lessons is a common problem in the schools I visit. It must be tackled at a whole-school level, with consistent rules, active monitoring, and appropriate sanctions. However, in terms of what you can control, I advise "starting" your Do Now - in other words, beginning the countdown for however long you want students working on your Do Now - when you have a critical mass of students in the room. If you ask students to transfer their answers from their books to their mini-whiteboards one question at a time when you review answers to the Do Now, those latecomers can join in at that stage so they do not miss out entirely.

Reason 2: The teacher needs to keep reminding students of the Do Now routine (e.g. don't copy the question out, do the working out in your books, silence when working on the questions, etc)

Solution: When introducing anything new - such as a different way of running your Do Now - the routine is unfamiliar to students. So, it is inevitable that the first few iterations will take longer than you would hope. But don’t cut corners or lower your standards. Invest the time in perfecting the routine now, safe in the knowledge it will save time in the many Do Nows to come. You can speed things up by initially reducing the content demands - make your first few Do Nows relatively easy so more of students' attention can be on the routine rather than the content of the Do Now.

Reason 3: Students take longer than they should to answer each question

Solution: Students often need an incentive to work briskly, especially during the Do Now. Four things help here. First, start a visible timer when you have a critical mass of students in the room. Second, circulate the room, then do the register, and then circulate again. Third, remind students that they will be asked to show their answers to each question on their mini-whiteboards and will be held accountable if they do not. Fourth, ensure students know the purpose of the Do Now - if they think it is just a few questions to keep them busy, they will likely labour over it.

Reason 4: Students work swiftly through the Do Now, but it still takes them a long time to finish all the questions

Solution: The Do Now is probably too long. When planning a Do Now, I advise aiming for most students to finish it in 5 minutes. For maths, this usually means a 4-question Do Now, made up of single-part, predominantly procedural questions. Even if students could answer more questions in that time, it will take you too long to review the answers properly.

This is also why I advise not using the Do Now to assess prerequisite knowledge for the upcoming lesson. Topics do not require the same number of prerequisite knowledge questions, so you cannot have a consistent structure for your Do Now. Also, you lose the flexibility to move on if students struggle with a question in the Do Now. I advise making the Do Now a spaced retrieval opportunity, using content unrelated to that of the lesson, and assessing prerequisite knowledge in a separate lesson phase after the Do Now.

Reason 5: Students get most of the questions wrong, so time is needed to model and recheck for understanding.

Solution: Don't pitch your Do Now too hard. A success rate of around 80% is a good goal. So, for a four-question Do Now, you should write it expecting the average student in your class to get 3 out of the 4 questions correct. At most, you should need to model and recheck for understanding for two of the questions. If you need to do more than this, your Do Now is too hard for your class.

Reason 6: Students get most of the questions correct, but the Do Now is still taking too long

Solution: Many teachers I observe have a habit of spending too long after a check for understanding reveals knowledge is secure. If the mini-whiteboards show that 80%+ of your students have the correct answer, don’t be tempted to ask one student to explain their thinking and then another student to comment on that answer. Instead, confirm what that answer is - writing it down and adding a quick verbal explanation - and then move on. Aim to do so within 7 seconds. Your time is better saved for the questions where students struggle.

Reason 7: Responding when students' knowledge is not secure is taking too long

Solution: When students' mini-whiteboards show fewer than 80% know the correct answer, do not be tempted to probe students more, especially if you can identify the nature of the misunderstanding from their answer. If students knew how to answer the question, they would have written the correct answer when you first asked them to. Instead, offer a clear and concise explanation, referring to common wrong answers where appropriate. Then, use the time you save to get more reliable evidence of understanding by asking all students to respond to a follow-up question.

If you are interested in some online, on-demand CPD on the Do Now, I have a 90-minute course available here. Once you purchase the workshop, you can share the clips and materials with all your staff or department as often as you like, for no extra cost.