Class 5 maths

Place Value
  • Rounding  -  They are not exact figures but they are close to the exact figures.
    • eg: Use the nearest multiple of 10
    • A number at the midway point is always rounded to the next highest multiple
  • Roman Numbers 
    • V & L are never substacted
    • I can be substracted from V and X only 
    • X can be subtracted from L and C only
    • V and L are never repeated
    • Repeating a numeral up to three times represents addition of the number. For example, III represents 1 + 1 + 1 = 3. Only I, X, C, and M can be repeated; V, L, and D cannot be, and there is no need to do so.
 Multiplication & Division
  • Numbers that are multiplied are called the factors and the answer is called the product
  • When you multiply by 10, 100, the product will have at least the same number of zeros as the factors
  • Dividend, divisor, quotient and remainder
    Quotient * Divisor + Remainder = Dividend
    • Samar and Suraj walked 189 km over 11 days, howmany km did they walk in a day
    • Tailor cut 35 meters to kame 15 pillow cases. How many meters of cloth used for each pillow case.


FRACTIONS

Types of fractions

  • Like fractions-have same denominator
  • Proper fractions-have a value less than 1.numerater smaller than denominator
  • Equivalent fractions-multiply the numerator and denominator by same number
  • Checking equivalent fractions - cross multiply
  • Fraction in its lowest term -only common factor is 1
Compare/add/substract 2 different fractions
  1. Find LCM of the 2 denominators 
  2. Convert the fractions into equalent fractions having the denominator as LCM from step1.
  3. compare/add/substract the equivalent fractions & reduce to lowest term as required
  4. Tips
    1. In unlike fractions iwth the same numerator, the fraction with greater denominator is the smaller fraction 
Add/substract  Mixed numbers
  • Method1
    1. Add the whole numbers
    2. Add fractions
    3. Add the fraction and whole numbers
  • Method2
    1. Convert the mixed numbers into improper fractions
    2. change to equivalent fractions and Add them
    3. Converst into mixed number
Multiplication of Fractions:
  1. Write the whole number as fraction
  2. multiply the numerators & denominators
  3. simplify
Reciprocals
  • 2 numbers who's product is 1

Divisions of fractions(Whole number by fraction, fraction by whole number, fraction by fraction)
  1. write whole number as fraction
  2. Find reciprocal of the divisor
  3. multiply dividend and the reciprocal of the divisor
  4. write in lowest term

Decimals
  • 1m=100cm
    • 5m 20cm=5m and 20/100m = 5.20m
  • 1km=1000m
    • 2km and 350 m = 2.350km
  • Comparing and Ordering Decimals
  • Addition/substraction of decimals
    • 0.4+0.6=
    • 0.8+0.5=
    • 1.3-0.6=
  • Multiplication of Decimals
    • multiply as in whole numbers ignoring the decimal
    • count the total number of decimal places in both numbers
    • starting from the right count the same number of decimal places in teh product and plce the decimal point there.
    • 0.05*6=
  • Dividing decimals by whole numbers
    • Place the decimal point in the quotient directly above teh decimal point
    • Divide as if you are dividing whole numbers.
Perimeter, Area and Volume(Rectangle, Square & Triangle)
  • Perimeter is Distance Around the edge of a figure.
    • Rectangle: 2*(l+b) cms, l*b sq cm
  • Area is the amount of surface a figure covers
  • Area of irregular shapes

Measurements
10 millimeters (mm) =1 centimeter (cm)
10 centimeters =1 decimeter (dm) = 100 millimeters
10 decimeters =1 meter (m) = 1,000 millimeters
10 meters =1 dekameter (dam)
10 dekameters =1 hectometer (hm) = 100 meters
10 hectometers =1 kilometer (km) = 1,000 meters


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