Carpentry & Building Construction

Math Activities :

Converting Decimals to Percents

A number can be expressed as a fraction, a decimal, or a percent. For example, 1/2 = 0.5 = 50 percent. Carpenters need to be able to convert decimals to percents, especially when figuring expenses and income related to a job. Percent means per one hundred or by the hundred. The symbol for percent is %. A decimal is a number expressed in powers of ten.

To convert a decimal to a percent, multiply by one hundred. A quick way to do this manually is simply to move the decimal point two places to the right. If using a calculator, input the decimal and then multiply the decimal by 100. In either case, add the percent symbol to the result.

 Terms, Symbols, & Abbreviationspercent - by the hundreddecimal - number expressed in powers of 10% - percent symbol

Practice Exercise

 Convert the decimal 0.225 to a percent. Step 1 Move the decimal point two places to the right. 0.225 becomes 22.5 OR, use a calculator: Multiply the decimal by 100. 0.225 × 100 = 22.5 Step 2 Add the percent symbol. The answer is 22.5%

Problem Exercises

 1 Convert 0.781 to a percent. A) .781 B) 0.781% C) 7.81% D) 78.1% 2 Convert 0.025 to a percent. A) 2.5 B) 2.5% C) 0.25 D) 0.25% 3 A carpenter just purchased nails and materials from a supplier. The sales tax is figured as 0.065 times the total cost on the receipt. What is the percent of sales tax? A) 0.06% B) 0.065% C) 6.5% D) 65% 4 A builder figured allowable waste material for a job by multiplying the total material by 0.150. What is the percent of waste? A) 15.0% B) 1.50% C) 0.150% D) 115.0% 5 A mason ordered a shipment of blocks for a job and figured the waste at 0.030. What is the percent of waste for the block materials? A) 0.03% B) 3.0% C) 30% D) 030%