Elementary Arithmetic and 68453i65409u6yit -548u Yp95843w

Unit – Rates, Ratios, Proportions

Rates

A car travelled 348 km in 4 hours .Write the unit rate that describes how fast the car was going.

348 4 4 4 87 1 The car travelled 87 km per hour.

Ratios
A ratio is comparison of measured quantities.
It can be written in two ways:
1. 5:6
2. 5/6

Proportions A proportion is a statement that two ratios are equal.
1. 4:6 = 2:3
2. 4/6 = 2/3

Fractions into Decimals Divide numerator with denominator
1. 2/5 = 0.4
2. 6/20 =0.3 Fractions into Percent
Change the fraction to decimal first. Then multiply the decimal by 100.
1. 4/5 = 0.4 =0.4 * 100
=40%

2. 8/40
=0.2 * 100
=20%

Decimals to fraction
Count the decimal places. Reduce
1. 0.432
=432/1000
=54/125
2. 1.52
=152/100
=76/50
=38/25

Decimal to Percent

Multiply with the decimal with 100.
1. 0.45
=0.45 * 100
=45%
2. 0.325
=0.325 * 100
=32.5%

Percent to Fraction
Take the fraction and place it over 100.
1. 25%
=25/100
=1/4
2. 16%
=16/100
=4/25 Percent to Decimal
Take the percent and place it over 100. Then, divide numerator with denominator.
1. 30%
=30/100
=0.3
2. 80%
=80/100
=0.8

Unit – Powers
We use powers to express repeated multiplication. “3” is the Base.
“5” is the exponent.
Writing powers
Write each of them as power.
1. 3 * 3 * 3 * 3
=
2.
=2 * 2 * 2 * 2
Importance of brackets.

Base = -2
Exponent = 4
Here the