# The Number System

## Adding Decimals to Make Them As Close to One as Possible

Directions: Using the digits 1 to 9 at most one time each, fill in the boxes to make three decimals whose sum is as close to 1 as possible. Source: Robert Kaplinsky

## Graphing Points on a Coordinate Plane

Directions: Make four points using the integers -4 to 4 at most one time each so that each point is in a different quadrant. Source: Robert Kaplinsky

## Undefined Quotient with Fraction Division

Directions: Using the digits 0 to 9 at most one time each, fill in the boxes to create at least two different examples where the quotient is undefined. Source: Daniel Luevanos

Directions: Using the digits 1 to 9 at most one time each, fill in the boxes to make the smallest (or largest) sum. Note: This problem’s difficulty can be adjusted by altering the number of digits (boxes), picking smallest or largest, or by picking either a positive, negative, or both. Source: Robert Kaplinsky

## Subtracting Decimals (Middle School)

Directions: Using the digits 1 to 9 at most one time each, fill in the boxes to make the smallest (or largest) difference. Note: This problem’s difficulty can be adjusted by altering the number of digits (boxes), picking smallest or largest, or by picking either a positive, negative, or both. Source: Robert Kaplinsky

## Dividing Decimals (Middle School)

Directions: Using the digits 1 to 9 at most one time each, fill in the boxes to make the smallest (or largest) quotient. Note: This problem’s difficulty can be adjusted by altering the number of digits (boxes), picking smallest or largest, or by picking either a positive, negative, or both. Source: Robert Kaplinsky

## Multiplying Decimals (Middle School)

Directions: Using the digits 1 to 9 at most one time each, fill in the boxes to make the smallest (or largest) product. Note: This problem’s difficulty can be adjusted by altering the number of digits (boxes), picking smallest or largest, or by picking either a positive, negative, or both. Source: Robert Kaplinsky

## Dividing Two-Digit Numbers (Middle School)

Directions: Using the digits 1 to 9 at most one time each, fill in the boxes to make the smallest (or largest) quotient. Note: This problem’s difficulty can be adjusted by altering the number of digits (boxes), picking smallest or largest, or by picking either a positive, negative, or both. Source: Robert Kaplinsky