Question

Activity 5.4 What Are You Made of 30g Now, moving left to right, compare digits that have the same place value. The digit in the ones and tenths places is the same in bosh numbers. In the hundredths place, 8 is gremer than 5, and it follows that 2.682.657. Procedure Comparing Decimals 1. First compare the integer parts (to the left of the decimal point). The number with the larger integer part is the larger number 2. If the integer parts are the same, compare the fractional parts (to the right of the decimal point) a. Write the decimal parts as fractions with the same denominator and compare the fractions. b. Line up the decimal points and compare the digits that have the same place value, moving from left to right. The first number with the larger digit is the larger number. 6. a. Use the method just described to determine if an average person has more sodiun or potassium in his body. b. Does the average person have more cobalt or iron in their body? Rounding Decimals In Chapter 1 you estimated whole numbers by a technique called rounding off, or rounding for short. Decimals can also be rounded to a specific place value. Example 4Round the weight of sodium in a 150-pound body to the tenths place. SOLUTION Observe that 0.165 has a 1 in the tenths place and that 0.165>0.1. So the task is to deter- mine whether 0.165 is closer to 0.1 or 0.2. 0.15 is exactly halfway between 0.1 and 0.2. 0.165 0.15, so 0.165 must be closer to 0.2 There is approximately 0.2 pound of sodium in a 150-pound body 310 Chapter D Problem Solving with Mixed Numbers and Decimals Procedure Rounding a Decimal to a Specified Place Value 1. If the specified place value is 10 or highet, drop the fractional part and round the resule- ing whole number 2. Otherwise, locate the digit with the specified place value. 3. If the digit directly to the right is less than 5, keep the digit in step 2 and delete all the digits to the right. 4. If the digit directly to the right is greater than or equal to 5, increase the digit in step 2 by I and delete all the digits to the right. Example 5 Round 279.583 to the ones place SOLUTION the same or increase by 1. Basically, you want to know whether the number is closer to 279 or 280. Since the tenths digit is 5, the number rounds to 280 (following step 4 in the procedure). 7. Copper's weight of 0.00023 pound, rounded to the nearest ten-thousandth place, is 0.0002 pound. Explain how this answer is obtained. 8. a. What is the weight of sodium, rounded to the nearest hundredth? b. What is cobalt's weight, rounded to the nearest ten-thousandth? Converting Fractions to Decimals 9, seven-tenths of the students in your class have a family dog or cat at home, write 곯 as a decimal In Problem 9, the fraction was written as a decimal by reading the number aloud and writ- ing its decimal form. All fractions can be written as decimals, even if their denominator is not a power of 10. Procedure Converting a Fraction to a Decimal 1. Using the long division format, divide the denominator into the numerator. 2. Place a decimal point to the right of the ones place in the dividend and a decimal point directly above it in the quotient. 3. Divide, adding as many zeros to the right of the decimal as necessary. 4. Round to the desired place value.

Answer 1

Values are not given for some questions, but i solved one such question with assumed values. The rest can be solved by referring to the solved questions as they are similar.

6 (a) 2-65 re. Sodiun--2 tawium → 2 te Aeimal 8 >5 en- place o: o. o Thousaud Ten-thousandth

2 than oDo3 ooo 23ャthe ten Step i :Use 10 10 value Snce, there»