Would you use count on or doubles to solve? why? 3+4

Which equation and solution can be used to solve this problem? thirteen less than a number is sixteen. 13-n=16: add 13 to both sides. the answer is 29. n+13=16: subtract 13 from both sides. the answer is 3. n+16=13 subtract 13 from both sides. the answer is 3. n-13=16: add 13 to both sides. the answer is 29.

Plz ( true - false) all triangles have interior angles whose measure sum to 90.

Cuántos triángulos forman un diamante