To divide a decimal by a whole number, place the decimal point in the quotient directly above the decimal point in the dividend. 3 cannot be divided by 5, so write 0 in the ones place. Bring down 4 to make 34. 34 ÷ 5 = 6 with a remainder of 4. Bring down 5 to make 45. 45 ÷ 5 = 9. So, 3.45 ÷ 5 = 0.69. Key formula: Align the decimal point in the quotient with the dividend. Answer: 0.69