The Davidson Group

Add within 20 without crossing 10

$0.99

Subtract within 20 without crossing 10

$0.99

Subtract within 20 w/o crossing 10 (2)

$0.99

Add & sub within 20 w/o crossing 10

$0.99

True & false # sentences within 20

$0.99

Link missing addends to subtract

$0.99

Link missing addends to subtract (2)

$0.99

Link missing addends to subtract (3)

$0.99

Link missing addends to subtract (4)

$0.99

Link missing addends to subtract (5)

$0.99

Link missing addends to subtract (6)

$0.99

Fact families within 20

$0.99

Add & subtract crossing 10 within 20

$0.99

Add by making 10 with 2 & 5 as addends

$0.99

Add by making 10 with 3 & 4 as addends

$0.99

Add by making 10 with 6 as an addend

$0.99

Add by making 10 with 7 as an addend

$0.99

Add by making 10 with 8 as an addend

$0.99

Add by making 10 with 9 as an addend

$0.99

2 & 5 as addends (2)

$0.99

2 & 5 as addends

$0.99

3 & 4 as addends (2)

$0.99

3 & 4 as addends

$0.99

6 as an addend (2)

$0.99

6 as an addend

$0.99

7 as an addend (2)

$0.99

8 as an addend (2)

$0.99

8 as an addend

$0.99

9 as an addend (2)

$0.99

Add crossing 10 within 20

$0.99

Equivalent number sentences

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2, 3, & 4 as subtrahends

$0.99

2, 3, & 4 as subtrahends (2)

$0.99

5 as a subtrahend

$0.99

5 as a subtrahend (2)

$0.99

7 as a subtrahend

$0.99

8 as a subtrahend

$0.99

8 as a subtrahend (2)

$0.99

9 as a subtrahend

$0.99

9 as a subtrahend (2)

$0.99

Subtract crossing 10 within 20

$0.99

Equivalent number sentences (2)

$0.99