Math

• Proportion


  An equation showing that 2 ratios/rates are equivalent
• Solving proportions


  Cross-multiply
• Proportion example


  • 287/7 = 32X/2802
  • x = 8
• Percent


  A ratio showing how a number compares to 100
• Bar diagram


  • amount/#
  • part
  • P%
  • whole (original)
  • 100%
  • part 'of whole (original)
• Proportion


  quantity % P = P/W 100
• Example 1 - Find Percents of Numbers

  • Diego's phone battery at 75% for 12-hour road trip
  • Kita's phone battery at 12% for 18-hour usage
• Example 2 - Use Percents Greater than 100%


  • Adult teeth are 160% of baby teeth
• Example 3 - Use Percents Less than 1%

  • Distance from Earth to Moon is 0.27% of distance from Earth to Sun
• The value that is greater than 100% of the original value is greater than the original value
• The value that is less than 1% of the original value is less than the original value
• Find 0.08% of 720


  Part of whole = 0.08% of 720 = 0.576
• Find 162.5% of 200


  Part of whole = 162.5% of 200 = 325
• Find 0.3% of 60


  Part of whole = 0.3% of 60 = 0.18
• Find how many ounces of apples to get 100% of daily vitamin C

  8 oz apples = 8% of daily vitamin C, so 100 oz apples = 100% of daily vitamin C
• Water is 2 parts hydrogen and 1 part oxygen (H2O)
• For one molecule of water, each atom has the atomic mass unit, u, shown
• What percent of the mass of a water molecule is hydrogen?