Math Review
Math Review. Consumer Economics. Math Review – Section 1. Objectives: Identify each position of the decimal number system Write numbers or amounts in word form Round numbers to approximate an answer Round numbers. The Decimal Number System. Decimal Number System
Math Review
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Math Review Consumer Economics
Math Review – Section 1 • Objectives: • Identify each position of the decimal number system • Write numbers or amounts in word form • Round numbers to approximate an answer • Round numbers
The Decimal Number System • Decimal Number System • Also called the Hindu-Arabic system • Number system that uses base 10 • Based on 10 digits • A digit is a numeral
The Decimal Number System • Decimal Number System • A dot called a decimal point separates whole numbers from decimal numbers • The names of the digits to the left and right of the decimal point are called position or places • Commas are used to the left of the decimal point to separate each group of three digits • Digits to the left form whole number parts • Digits to the right of the decimal point form the decimal part
Word Forms • Word Forms • Numbers or amounts may be spelled out • The decimal point is represented by the word and
Word Forms • Check writing • Bank requires you to write the amount in both number and word forms • Cents are written as a fraction of a dollar • 50 Cents = 50/100 • Written along side the word form
Check for Understanding Name ___________________________ Date_________________ • Identify each numeral and decimal position. Then write the number in word form.
Rounding • Approximate • To come near to an amount rather than give an exact number • $219.95 will round up to $220 • $219.05 will round down to $219.00
Rounding • Steps • Determine the position (place) being rounded • If the digit to the right of the position (place) is 5 or more, round up by 1Example: 6.8 rounds up to 7 (8 is more than 5) • If the digit to the right of the position is less than 5, do not round up. Drop all digits from that position to the right Example: 6.4 rounds down to 6 (4 is less than 5)
Check for Understanding Name ___________________________ Date_________________ • Round each number to its nearest place value
Math Review – Section 2 • Objectives: • Identify terms used with addition • Align numbers correctly for adding • Align decimal points in addition • Add negative numbers • Combine addition and subtraction
Addition • Addition • The process of combining two or more numbers and arriving at a larger number • Each number is called an addend • The solution is called the sum, total, or amount 931 + 27 958 Addend Addend Sum, Total, or Amount
Addition • Align numbers correctly for adding • Align in columns • Tens above tens, hundreds above hundreds, etc. 8,712 256 3,421 951 + 13,340
Check for Understanding Name ___________________________ Date_________________ • Align the following addends properly, then find the sum, total or amount. 8,360 24,058 15 321,789 +8,435,905 423 6,729 +18,705 71 60,552 194 +7086
Addition • Align decimal points • Number of decimal places is determined by addend with the largest number of decimal places 5,146.11 56.044 10.07 694.081 + 1,237.0548 7,148.3598 Addend with largest number of decimal places Answer has 4 decimal places
Check for Understanding Name ___________________________ Date_________________ • Align the following decimal addends properly, then find the sum, total or amount. 23.48613 53,987.2 19,420.987 +4907 629.543 24.0587 13.4 321.78 +8,435.90573 3.9876 567.905 +197,534.032
Adding Negative Numbers • You may be required to add a column of negative numbers • Add as if they were positive numbers, placing the negative sign before the answer 47 83 23 15 168
Check for Understanding Name ___________________________ Date_________________ • Align the following negative addends properly, then find the sum, total or amount. 54 652 23,953 5,620 917 3240 5 2174 328,031 321 43 7,890
Adding Negative Numbers • Combine addition and subtraction • Total the positive numbers • Total the negative numbers • Subtract the two • If the total of the positive numbers is larger, then the answer is positive • If the total of the negative numbers is larger, then the answer is negative
Adding Negative Numbers • Combine addition and subtraction 25 13 88 7 26 25 + 13+ 7 = 45 Total of Positive Numbers - 88 – 26 = -114 Total of Negative Numbers -114 +45 -69 Subtract Solution
Check for Understanding Name ___________________________ Date_________________ • Align the following addends properly, then find the sum, total or amount. 2,956 658 21,438 3 7,525 8,094 2349 27 1278 430 815 976