1. TechConnect
Concrete
Math

2. Definitions
Addition – process of totaling two or more numbers to find another number called a sum
Example: = 17
Calculate – to perform a mathematical process
Caret – the symbol ^ used to indicate where something is to be inserted
Digit – any one of the ten symbols, 0 to 9, by which all numbers can be expressed
Division – opposite (inverse) operation of multiplication
Example: 16/2 = 8 as compared to 8 x 2 = 16

3. Modular – pertaining to nominal units based on a 4-inch modular
Decimal – fraction with an unwritten denominator of 10 or some power of 10; indicated with a point before the number
Example: 0.1 = 1/10
Fraction – part of a whole; represents one or more equal parts of a unit
Modular – pertaining to nominal units based on a 4-inch modular

4. Nominal size – theoretical size that may vary from the actual
• Multiplication – an abbreviated process of adding a number to itself a specified number of times
Example: 6 x 3 = 18 as compared to = 18
Nominal size – theoretical size that may vary from the actual
Example: a 2 x 4 stud is actually 1 ½ inches by 3 ½ inches
Percent – one part of a hundred; calculated on the basis of a whole divided into one hundred parts
Problem – mathematical proportion
Proportional – being relatively equal in size and quantity
Example: 1:1:3 = 0.5:0.5:1.5

5. Subtraction – opposite (inverse) operation of addition
Ratio – relationship in quantity, amount, or size between two or more things
Subtraction – opposite (inverse) operation of addition
Example: 8 – 4 = 4 as compared to = 8
• Whole number (integer) – any of the natural numbers, both positive and negative, that represent a complete item
Example: 25 is a whole number as compared to ¾, a fraction or part of a whole

6. Symbols

7. Place Values of Whole Numbers

8. Adding Whole Numbers
Set up the problem by writing units under units, tens under tens, and so on.
Add each column separately, beginning at the top of the units column.
If the sum of any column is two or more digits, write the units digit in your answer and carry the remaining digit(s) to the top of the next column to the left.
Add any carried digit(s) above the column with that column.

9. Subtracting Whole Numbers
Set up the problem by writing units under units, tens under tens, and so on.
Subtract each column separately, beginning at the bottom of the units column.
If a digit in the number being subtracted is larger than the digit above it, “borrow” 1 from the top digit in the next column to the left, decreasing that digit by one and increasing the digit being subtracted by ten.

10. 4. If there is nothing to borrow in the next left column (column contains a zero), first borrow for that column from its next left column.
5. Check your subtraction by adding your answer to the subtracted number.

11. Multiplying Whole Numbers
Set up the problem by writing the larger number (original number) above the smaller number (multiplier), writing units under units, tens under tens, and so on.
If the multiplier contains only one digit, multiply each digit in the original number by it, working from right to left.
If the multiplier contains more than one digit find partial products.
Add the partial products.

12. Dividing Whole Numbers
Set up the problem by writing the original number (number to be divided) inside a division frame, and by writing the divisor (number you are dividing by) outside the frame.
Determine how many times the divisor will go into the first digit of the original number. If it will not, write a zero in the answer space directly above the first digit, and then determine how many times the divisor will go into the first two numbers of the original number.

13. 3. Multiply the divisor by the answer (digit above frame); write this answer under the digit(s) that divisor went into, and subtract.
4. Bring down the next unused digit from the original number and place it to the right of the subtracted difference (remainder) – even if the remainder is zero.
5. Determine how many times the divisor will go into this new number; write your answer in the answer space above the digit that was brought down.

14. 6. Multiply the divisor by the last digit you wrote in the answer; write this product under the digits that divisor went into and subtract.
7. Continue this process until all numbers in the original number have been used.
8. Write any remaining subtracted differences as a remainder.
9. Check the answer by multiplying your answer times the divisor and adding the remainder to this number.

15. Types of Fractions
Proper – Top number of fraction (numerator) is smaller than bottom number of fraction (denominator)
Improper – Top number of fraction (numerator) is larger than bottom number of fraction (denominator)
Mixed numbers – Contains a whole number and a proper fraction

16. Reducing Fractions to Lowest Terms
Divide the numerator and denominator by the largest whole number that will go into each evenly.

17. Converting Mixed Numbers to Improper Fractions
Multiply the whole number by the denominator of the fraction.
Add your answer to the nominator.
Place this sum over the original denominator.

18. Converting Improper Fractions to Mixed Numbers
Divide the numerator by the denominator.
Place the remainder over the denominator.
Reduce this fraction if necessary.
Add the reduced fraction to the whole number obtained by dividing the numerator by the denominator.

19. Adding Fractions • Unlike fractions • Like fractions
1. Add the numerators.
2. Place the sum of the numerators over the common denominator.
3. Convert to mixed numbers and reduce as required.
• Unlike fractions
1. Change to like fractions.
2. Add like fractions and reduce or convert to mixed numbers as required.

20. Mixed numbers Add whole numbers.
Add fractions, first finding common denominators if necessary, and reduce or convert to mixed numbers as necessary.
Add the sums of steps 1 and 2.

21. Subtracting Fractions
• Like fractions
Subtract the smaller numerator from the larger numerator.
Place the subtraction answer over the common denominator.
Reduce to lowest terms as required.
Unlike fractions
Change to like fractions.
Subtract now as for like fractions.
Reduce to the lowest terms as required.

22. Mixed numbers Convert mixed numbers to like fractions.
Borrow a one from the original whole number if needed, convert the one to a like fraction, and add it to the smaller fraction.
Subtract the whole number from the whole number and the like fraction from the like fraction.

23. Multiplying Fractions
Convert mixed numbers to improper fractions, if necessary.
Multiply numerators by numerators and denominators by denominators.
Write the product of the numerators over the product of the denominators.
Convert improper fractions to mixed numbers and reduce as required.

24. Place Values

25. Adding Decimals
Set up problem as for addition of whole numbers, aligning decimal points directly under each other.
Add each column of numbers as if whole numbers.
Locate the decimal point in the answer by placing it directly under the decimal points above.

26. Subtracting Decimals
Set up problem for subtraction of whole numbers, aligning decimal points directly under each other.
Subtract each column of numbers as if they were whole numbers.
Locate the decimal point in the answer by placing it directly under the decimal points above.
Check your subtraction by adding your answer to the subtracted number.

27. Multiplying Decimals
Set up the problem and multiply as if you were multiplying whole numbers.
Count the number of decimal places to the right of the decimal points in the multiplier and the original number.
Locate the decimal point in the answer by beginning at the far right digit and counting off as many places to the left as the total decimal places found in step 2.

28. Dividing Decimals
Set up the problem as you would for the division of whole numbers.
Move the decimal point in the divisor to the right of the far right digit in the divisor.
Move the decimal point in the original number to the right by the same number of decimal places that you moved the decimal point in the divisor, adding zeros to the original number if necessary.
4. Place a decimal point in the answer space directly above the repositioned decimal point in the original number.

29. 5. Divide as for whole numbers.
6. Check your division by multiplying the original divisor (before the decimal point was moved) by your answer and adding any remainder to this number.

30. Converting Decimal Fractions to Common Fractions
Remove the decimal point.
Place the number over its respective denominator (10s, 100s, 1000s).
Cancel zeros when possible.
Reduce to the lowest term.

31. Converting Common Fractions to Decimal Numbers and Percentages
• Fractions to decimals – divide the numerator by the denominator
• Fractions to percentages
Convert the fractions to decimals by dividing the numerator by the denominator.
Move the decimal point in the answer two places to the right.
Place the percent symbol after the number.

32. Decimal and Fractional Equivalents

33. Converting Percentages to Fractions and Decimal Numbers
Drop the percent symbol.
Place the number over 100.
Reduce to lowest terms if necessary.
• Percentages to decimals
Drop the percent symbol.
Move the decimal point two places to the left.

34. Solving Percentage Problems
1. Write the unknown as “X”.
2. Write the percent (known or unknown) as a fraction with a denominator of 100.
3. Write the part and the whole as a fraction, writing the part as the numerator and the whole as the denominator.
4. Set up the equation by writing the two fractions with an equal sign between them.
5. Solve the equation by multiplying the numerator of each fraction by the denominator of the other.
6. Divide each side of the equation by the multiplier of X.

35. Geometry Terms
• Geometric figure – shape formed by straight or curved lines
• Perimeter – outer limits or boundaries
• Linear – relating to, consisting of, or resembling a straight line
• Parallel – extending in the same direction; equal distance apart and never ending

36. • Right angle – angle formed by two lines perpendicular to each other; 90 degree angle
• Perpendicular – line or surface at a right
angle to another line or surface

37. • Diameter – distance between the outer
edges of a circle through the center point
• Radius – line from the center of a circle to any point on the edge of the circle

38. • Circumference – distance around the outer
edge of a circle
• Pi – Greek letter () representing the ratio of a circle’s circumference to its diameter; ratio approximately
• Area – measure of a flat surface; expressed in square units
• Volume – space occupied by a body; expressed in cubic units

39. • Cubic unit – unit with three equal dimensions including length, width, and height
• Cubic foot – volume of an object that is 1 foot long, 1 foot wide, and 1 foot high

40. Geometric Figures
• Square – figure having four sides of equal length and four right angles
• Rectangle – figure with two parallel ends of equal length, two parallel sides of equal length, and four right angles

41. • Triangle – figure having three sides and three angles
• Circle – flat round figure formed by one curved line; all points of the curved line are equidistant from the center point

42. • Parallelogram – figure such as a square, rectangle, or rhombus with two parallel ends of equal length and two parallel sides of equal length
• Rhombus – figure having no right angles and four sides of equal length

43. • Trapezoid – figure with only one pair of parallel sides

44. Equivalents
• Inch (”) – equal to one-twelfth of a foot (1/12) or one thirty sixth of a yard (1/36 yard)
• Foot (’) – equal to twelve inches (12”) or one-third of a yard (1/3) yard
• Yard – equal to three feet (3’) or thirty-six inches (36”)
• Rod – equal to sixteen and one-half feet (16 1/2’)
• Mile – equal to five thousand, two hundred and eighty feet (5280’)
• Degree – equal to 1/360 of a circle

45. Area • Square – use the formula: Area = Length x Width or A = LW
• Rectangle – use the formula: A = Length x Width or A = LW

46. • Circle – use the formula: Area = r2
• Triangle – use the formula: Area = 1/2 base x height, or A = 1/2BH

47. • Parallelogram – use the formula: Area = Base x Height, or A = BH
• Trapezoid – use the formula: Area = ½ H (B1 + B2)

48. Volume
• Using the counting method: Cubic Units = Number of Cubes in Layer x Number of Layers
• Using the formula: Volume = Length x Width x Height

49. Estimating Cubic Yards
• Cubic Yards = Width x Length x Thickness divided by 27

50. Proportion
• To increase or decrease proportionally, multiply or divide each number in the ratio by the same number.

51. Oklahoma Department of Career and Technology Education
© 2006
Oklahoma Department of Career and Technology Education