## Subtracting Reverses

This extraordinary lesson combines base ten subtraction practice with an irresistible mystery. A pattern slowly reveals itself as the class compiles data.

## Fill the Stairs

Fill the Stairs requires the thoughtful placement of two-digit numbers in order from least to greatest, before all the numbers are known. Overall, it is a fun and compelling game that holds up after repeated playing.

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## Penny, Nickel, Dime

This version of Don’t Break the Bank is a hit with students, and also helps give a concrete meaning to place value by linking it to both money, addition, estimation, and multiplying by fives and tens. It takes very little time, so it can be used as a warmup, station activity, or in those five minutes before class ends. While …

## The Hundred Chart Game

Topics: addition, subtraction, strategy Materials: Two types of tokens (gems & pawns), hundreds chart Recommended Grades: 1, 2, 3 Common Core: 1.NBT.C.4, 1.NBT.C.5, 1.NBT.C.6, C2.NBT.B.5 Add and subtract 10s and 1s to pick up the tokens on the hundreds chart. Why We Love The Hundred Chart Game This game delivers tons of addition and subtraction practice in a way kids love. …

## The Calendar Problem

Topics: Multiplication, addition, Materials: Calendar, Hundreds chart, pencil and paper, calculator (optional) Common Core: 4.OA.1, 4.OA.3, 4.OA.5, 4.NBT.5, MP1, MP2, MP3, MP6, MP7, MP8 How can you add up these numbers so quickly? Why we love this lesson Simple to launch, instantly engaging and accessible, this puzzle is a beautiful demonstration of the usefulness of multiplication. Not only that, figuring …

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## The Power of 37

Topics: Multiplication, patterns, Materials: Pencil & paper Common Core: 4.NBT.1, 4.NBT.5, 5.OA.1, 5.OA.2, 5.NBT.5, MP1, MP2, MP3, MP6, MP7, MP8. How does multiplying by 37 have this strange effect? This problems in multiplication is designed to give students the practice they need once they understand the basic idea of multiplication, with a context to provide motivation and deeper understanding. The …

## Horseshoes (+/-)

Topics: Addition, subtraction, estimation, comparisons. Materials: Card deck, pencil and paper, white board/document camera. Grades: 2, 3, 4 Common Core: 2.NBT.B.5, 3.NBT.A.2 How close can you get to the target number with the digits provided? Why We Love Horseshoes Horseshoes combines arithmetic practice with complex thinking. Students make their own choices about how to combine the four numbers and get immediate feedback …

## Broken Calculators

Topics: Addition, Subtraction, Skip Counting, Multiplication, Logic Materials: Scratch paper and pencil, handouts (optional) Recommended Grade: 3, 4 Common Core: 3.OA.A.3, 3.OA.A.4, 3.OA.B.5, 3.OA.D.8, 3.OA.D.9, 4.OA.A.4, 4.OA.C.5, MP1, MP2, MP3, MP6, MP7, MP8 Something is wrong with the calculators in each lesson. Can students reach the target number despite the broken buttons? Why We Love Broken Calculators The premise is simple, but …

## 1-2-3 Nim on a 10-Frame

Topics: logic, patterns, addition to 10, counting to 10, subtraction Materials: One 10-frame and at least ten counters per pair of students Recommended Grades: K, 1 Common Core: K.CC.A.2, K.CC.B.4, K.CC.B.5, K.OA.A.1, K.OA.A.2, K.OA.A.4, K.OA.A.5, 1.OA.B.4, MP1, MP7 How to Play Players take turns placing one, two, or three counters on the open squares of a 10-frame. Whoever fills up …

## Counting Collections

Topics: Counting, skip counting, addition, multiplication (optional) Materials: Paper, pencil, objects of many types (button, beans, stones, pencils, markers, blocks, etc.) Target Grades: K, 1, 2, 3 Common Core: K.CC.A.1, K.CC.A.2, K.CC.A.3, K.CC.B.4, K.CC.B.5, K.MD.B.3, 1.NBT.A.1, 1.NBT.B.2, 1.NBT.B.2.a, 1.NBT.B.2.b, 1.NBT.B.2.c, 2.OA.C.4, 3.OA.A.1, MP1, MP6 Kids love to count things. This is a simple exercise, but a great way to get kids excited about arithmetic. Counting …