Add multiples of 10 within 40

$0.99

Add without crossing the 10 within 40

$0.99

Add crossing the 10 within 40

$0.99

Add 2-digit #s & 1-digit #s within 40

$0.99

Add 2-digit #s within 40 w/o renaming

$0.99

Add 2-digit #s within 40 with renaming

$0.99

Add 2-digit numbers within 40

$0.99

Add within 40

$0.99

Add 2-digit numbers within 100

$0.99

Add mult of 10 to mult of 10 within 100

$0.99

Add multiples of 10 within 100

$0.99

Add 2-digit #s without renaming

$0.99

Add & subtract multiples of 10 within 40

$0.99