Write each number in standard form. 21. \( \left(3 \times 10^{7}\right)+\left(8 \times 10^{4}\right) \) 22. \( \left(6 \times 10^{4}\right)+\left(5 \times 10^{2}\right)+\left(1 \times 10^{0}\right) \) 23. \( \left(5 \times 10^{8}\right)+\left(8 \times 10^{7}\right)+\left(7 \times 10^{5}\right)+\left(2 \times 10^{3}\right)+\left(4 \times 10^{0}\right) \) 24. \( \left(4 \times 10^{6}\right)+\left(7 \times 10^{4}\right)+\left(7 \times 10^{2}\right)+\left(3 \times 10^{1}\right) \) 25. \( \left(5 \times 10^{9}\right)+\left(9 \times 10^{6}\right)+\left(5 \times 10^{3}\right)+\left(9 \times 10^{2}\right)+\left(6 \times 10^{0}\right) \)

Sure! Here's each number written in standard decimal form: **21.** \( \left(3 \times 10^{7}\right) + \left(8 \times 10^{4}\right) \) \[ 3 \times 10^{7} = 30,000,000 \] \[ 8 \times 10^{4} = 80,000 \] \[ 30,000,000 + 80,000 = 30,080,000 \] **Standard Form:** **30,080,000** --- **22.** \( \left(6 \times 10^{4}\right) + \left(5 \times 10^{2}\right) + \left(1 \times 10^{0}\right) \) \[ 6 \times 10^{4} = 60,000 \] \[ 5 \times 10^{2} = 500 \] \[ 1 \times 10^{0} = 1 \] \[ 60,000 + 500 + 1 = 60,501 \] **Standard Form:** **60,501** --- **23.** \( \left(5 \times 10^{8}\right) + \left(8 \times 10^{7}\right) + \left(7 \times 10^{5}\right) + \left(2 \times 10^{3}\right) + \left(4 \times 10^{0}\right) \) \[ 5 \times 10^{8} = 500,000,000 \] \[ 8 \times 10^{7} = 80,000,000 \] \[ 7 \times 10^{5} = 700,000 \] \[ 2 \times 10^{3} = 2,000 \] \[ 4 \times 10^{0} = 4 \] \[ 500,000,000 + 80,000,000 + 700,000 + 2,000 + 4 = 580,702,004 \] **Standard Form:** **580,702,004** --- **24.** \( \left(4 \times 10^{6}\right) + \left(7 \times 10^{4}\right) + \left(7 \times 10^{2}\right) + \left(3 \times 10^{1}\right) \) \[ 4 \times 10^{6} = 4,000,000 \] \[ 7 \times 10^{4} = 70,000 \] \[ 7 \times 10^{2} = 700 \] \[ 3 \times 10^{1} = 30 \] \[ 4,000,000 + 70,000 + 700 + 30 = 4,070,730 \] **Standard Form:** **4,070,730** --- **25.** \( \left(5 \times 10^{9}\right) + \left(9 \times 10^{6}\right) + \left(5 \times 10^{3}\right) + \left(9 \times 10^{2}\right) + \left(6 \times 10^{0}\right) \) \[ 5 \times 10^{9} = 5,000,000,000 \] \[ 9 \times 10^{6} = 9,000,000 \] \[ 5 \times 10^{3} = 5,000 \] \[ 9 \times 10^{2} = 900 \] \[ 6 \times 10^{0} = 6 \] \[ 5,000,000,000 + 9,000,000 + 5,000 + 900 + 6 = 5,009,005,906 \] **Standard Form:** **5,009,005,906**