Use type=number on more exercises with multiple inputs.

Summary:
Use type=number on Adding and Subtracting Complex Numbers.

Use type=number on Adding and Subtracting Decimal Word Problems

Use type=number on Adding Vectors

Use type=number on Angle Addition Postulate

Use type=number on Angles of a Polygon.

Use type=number on Area 1.

Use type=number on Area of Parallelograms.

Use type=number on Area of Squares and Rectangles.

Use type=number on Area of Triangles 1.

Use type=number on Areas of Trapezoids, Rhombi and Kites.

Test Plan: local, Chrome/OS X

Reviewers: tom, eater

Reviewed By: eater

CC: stephanie, alpert

Differential Revision: http://phabricator.khanacademy.org/D1030