Core Focus on Decimals & Fractions Dividing Decimals by Whole Numbers Lesson 2.5

Warm-Up 9 $ R4 Find the value of: 1.45 ÷ 5 2.$130 ÷ ÷ ÷ 8

Dividing Decimals by Whole Numbers Find quotients of expressions where decimals are divided by whole numbers. Lesson 2.5

Dividing Decimals with Whole Numbers 1.Divide as if both dividend and divisor are whole numbers. 2.Move the decimal point into the quotient directly above the decimal point in the dividend. 3.Insert zeros if necessary to hold place value. 4.Some answers will need to be rounded to a given place value.

Example 1 Joe bought 3.9 pounds of candy corn for a harvest party. He divided it among himself and nine friends. How many pounds of candy corn did each person get? Write the problem. 3.9 ÷ 10 Divide as if the divisor and dividend were whole numbers. Move the decimal point into the quotient directly above the decimal point in the dividend. Each person received 0.39 pounds of candy corn.

Example 2 Find the value of 2.97 ÷ 30. Divide as if the divisor and dividend were whole numbers. Move the decimal point into the quotient directly above the decimal point in the dividend ÷ 30 = Insert a zero on the end of the dividend. Continue dividing.

Good to Know! Sometimes you may need to round to a designated place-value. Divide until the quotient has one more place-value position than where it is being rounded to. (This helps you know whether to round up or down.) You may need to add one or more zeros at the end of the decimal dividend to find the quotient.

Example 3 Janease spent $3.22 to download three songs. Each song cost about the same amount. How much did she spend on each song? Round to nearest penny (hundredth) if necessary. Write the problem.3.22 ÷ 3 Divide as if the divisor and dividend were whole numbers. Continue until you have gone one more place value past the hundredth position. Insert a zero on the end of the dividend and continue dividing.

Example 3 Continued… Janease spent $3.22 to download three songs. Each song cost about the same amount. How much did she spend on each song? Round to nearest penny (hundredth) if necessary. Move decimal point up into the quotient. Round to nearest penny → 1.07 Janease spent about $1.07 on each song.

Example 4 Find the value of 16 ÷ 5. Place a decimal point in the dividend at the end of the whole number. Divide. Move the decimal into the quotient. 16 ÷ 5 = 3.2

Communication Prompt Do base-ten blocks allow you visualize the process of dividing decimals by whole numbers? Why or why not?

÷ ÷ 5 3.Sixteen people won $1, to split evenly. How much did each person receive? 4.If Martin paid $4.45 for 3 pounds of apples, how much did each pound of apples cost? Round to the nearest penny, if necessary. Exit Problems $62.50 $1.48 per pound