Run sheet

Comparing Tens and Ones

Grade 2 · Lesson 3 · 23 slides · blocked practice

The big idea

To compare two-digit numbers, compare the TENS first. Only if the tens are equal do the ones decide it.

Slide by slide

#	On the screen	What you say
1	Today — WARM-UP	Point at the five parts. Name where we are.
2	Count on by tens from 35, twice.	Boards up on three. This is yesterday's work — Counting by Tens or Ones. Do not help each other; I need to see what each of you kept.
3	45, 55 answer — own slide	Show me. Everyone at once. Check your own board against this.
4	Today — I DO	We are at I DO. Boards down and flat.
5	To compare two-digit numbers, compare the TENS first. Only if the tens are equal do the ones decide it.	Read this out. Do not explain it yet — the example explains it.
6	43 38 build 1 of 5	Compare 43 and 38.
7	43 38 4 tens vs 3 tens build 2 of 5	Tens first: 4 tens against 3 tens.
8	43 38 4 tens vs 3 tens 43 > 38 build 3 of 5	4 tens is more, so 43 is greater. The ones never mattered.
9	43 38 4 tens vs 3 tens 43 > 38 4 tens = 4 tens build 4 of 5	Now 43 and 47. The tens are the SAME.
10	43 38 4 tens vs 3 tens 43 > 38 4 tens = 4 tens 47 > 43 build 5 of 5	Only now do the ones decide: 7 is more than 3.
11	Which is greater, 52 or 49?	Now the same thing on a new one. Watch — nothing on your boards.
12	Tens: 5 against 4. 5 tens is more. 52 > 49 answer — own slide	I say every step aloud as I write it. The board keeps all of it.
13	Today — WE DO	We are at WE DO. Boards up.
14	Which is greater, 61 or 66?	Check the tens first — then decide whether you even need the ones.
15	Tens are equal. Ones: 6 > 1. 66 > 61 answer — own slide	Boards up. Everyone at once — check yours against this.
16	Which is greater, 28 or 71?	The ones look big on one of these. Do not let that decide it.
17	Tens: 7 > 2. 71 > 28 answer — own slide	Boards up. Everyone at once — check yours against this.
18	Today — YOU DO	We are at YOU DO. Boards down, books open.
19	Dimensions 2A — page 12	Open your books to this page. Wait — do not start yet.
20	Do — page 12	These are the book's own problems, same type as the three we have just done. Work them in the book.
21	Today — CLOSURE	Last part. Answers up.
22	“Have I compared the tens before I looked at the ones?”	This is the question to ask yourself every time, not just today.
23	Which is greater, 34 or 43?	One last board. Then we are finished.

Mini whiteboards, by segment

Segment	MWB	Time	Boards	What to hold
WARM-UP	retrieval	3-5 min	BOARDS UP	Question up, boards up on the count. Everyone shows at once — a child who waits to see a neighbour's board has not retrieved anything. Grade 2 may drop this if the previous lesson was a review — from Grade 4 it is not optional.
I DO	none — they watch	3-4 min	boards down	Boards DOWN and flat. This segment is watching, and a child writing is not watching. Say so once at the start of the year and then hold it.
WE DO	primary use	5-6 min	BOARDS UP	One step, then boards up. Do not let them run ahead to the answer — the point is that everybody is on the same step at the same time.
YOU DO	on the sheet	4-5 min	boards down	Boards down. This is the book's problems, worked where the work will be kept.
CLOSURE	answers displayed	2-3 min	boards down	Answers on the board, children check their own. Mark nothing here.

Watch for
28 vs 71 is built as a trap: 8 is the biggest digit on the page and it is in the smaller number. A child who answers 28 has compared the ones first, which is the exact error this lesson exists to prevent.