Illustration of a quadrilateral which has two adjacent sides equal and the other two sides equal. It…

Bilingual Counting Card featuring illustrations of four Sailfishes.

Bilingual Counting Card featuring illustrations of four Sandcastles.

English Counting Card featuring illustrations of four Sandcastles.

Spanish Counting Card featuring illustrations of four Sandcastles.

Bilingual Counting Card featuring illustrations of four Sponge Divers.

English Counting Card featuring illustrations of four Sponge Divers.

Spanish Counting Card featuring illustrations of four Sponge Divers.

Bilingual Counting Card featuring illustrations of four Starfishes.

Illustration of a trapezoid, with the median drawn. The median of a trapezoid is parallel to the bases,…

Illustration of the resultant vector when four vectors are acting upon a body at point P.