Express the sum using summation notation. Write out the sum. 2 3 16 + + 4 16+3 E K 2 1 N 16 6 = 0+0+...+0 + 4 6 16 + 3 = EN K = 1 k = 1 (Type the first, second, and final terms. Type fully Simplify your answer. Use integers or fractions for al Express the sum using summation notation. 1+2+3+ . . .+7 1+2+3+ . . .+7= > K = 1