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ESO Y2 · Mathematics
Numbers · Natural numbers

Powers

A video is shared by $1$ person, and every hour the number of people who have shared it triples. After $5$ hours, writing $3\cdot3\cdot3\cdot3\cdot3$ is tedious and easy to get wrong. That is what powers are for: a short way of writing repeated multiplication.

Before you start, make sure you know: Properties of powers (1st ESO)
Before you start, make sure you know: Prime numbers and prime factorisation (1st ESO)

What a power is

Move the sliders and see how powers grow (or shrink).

Practice★☆☆Not started
Express the following products as a power and state the base and the exponent in each case: a) $5 \cdot 5 \cdot 5 \cdot 5$ b) $12 \cdot 12 \cdot 12$ c)…

Express the following products as a power and state the base and the exponent in each case:

  1. a) $5 \cdot 5 \cdot 5 \cdot 5$
  1. b) $12 \cdot 12 \cdot 12$
  1. c) $2 \cdot 2 \cdot 2 \cdot 2 \cdot 2 \cdot 2$
  1. d) $10 \cdot 10 \cdot 10 \cdot 10 \cdot 10$
Solve
Practice★☆☆Not started
Work out the value of the following basic powers: a) $3^{4}$ b) $2^{5}$ c) $7^{2}$ d) $11^{0}$ e) $1^{25}$

Work out the value of the following basic powers:

  1. a) $3^{4}$
  1. b) $2^{5}$
  1. c) $7^{2}$
  1. d) $11^{0}$
  1. e) $1^{25}$
Solve

Multiplying and dividing powers with the same base

Visual justification of adding and subtracting exponents when multiplying and dividing powers with the same base, by expanding their factors 3² · 3⁴ = (3·3)·(3·3·3·3) = 3⁶ add the exponents 2 + 4 = 6 7⁵ : 7² = (7·7·7·7·7)/(7·7) = 7³ subtract the exponents 5 − 2 = 3
Practice★☆☆Not started
Apply the laws of indices to write the result as a single power: a) $3^{4} \cdot 3^{2} \cdot 3^{5}$ b) $a^{3} \cdot a^{4}$ c) $10^{2} \cdot 10 \cdot 10^{3}$ d)…

Apply the laws of indices to write the result as a single power:

  1. a) $3^{4} \cdot 3^{2} \cdot 3^{5}$
  1. b) $a^{3} \cdot a^{4}$
  1. c) $10^{2} \cdot 10 \cdot 10^{3}$
  1. d) $2^{6} \cdot 2^{6}$
Solve
Practice★☆☆Not started
Simplify to a single power using the division law of indices for powers with the same base: a) $5^{8} : 5^{3}$ b) $x^{10} : x^{7}$ c) $10^{6} : 10^{5}$ d)…

Simplify to a single power using the division law of indices for powers with the same base:

  1. a) $5^{8} : 5^{3}$
  1. b) $x^{10} : x^{7}$
  1. c) $10^{6} : 10^{5}$
  1. d) $\dfrac{2^{9}}{2^{4}}$
Solve
Practice★★☆Not started
Apply the laws of indices to simplify the following expressions to a single power: a) $2^5 \cdot 2^3 \cdot 2 =$ b) $(3^4)^3 : 3^7 =$ c) $\frac{5^8 \cdot 5^2}{5^7} =$

Apply the laws of indices to simplify the following expressions to a single power:

a) $2^5 \cdot 2^3 \cdot 2 =$

b) $(3^4)^3 : 3^7 =$

c) $\frac{5^8 \cdot 5^2}{5^7} =$

Solve

Power of a power, of a product and of a quotient

Visual justification of multiplying exponents in a power of a power, by expanding the factors (4³)² 4³·² multiply the exponents: 3 · 2 = 4⁶ = 4.096
Practice★☆☆Not started
Simplify the following expressions, leaving the result as a single power: a) $(4^{3})^{2}$ b) $(10^{5})^{4}$ c) $(x^{2})^{8}$

Simplify the following expressions, leaving the result as a single power:

  1. a) $(4^{3})^{2}$
  1. b) $(10^{5})^{4}$
  1. c) $(x^{2})^{8}$
Solve
Practice★★☆Not started
In a logistics warehouse, boxes are organised into cubic shelving units. A storage block consists of 4 shelving units in width, 4 in length, and 4 in height. If each…

In a logistics warehouse, boxes are organised into cubic shelving units. A storage block consists of 4 shelving units in width, 4 in length, and 4 in height. If each shelving unit contains 4 boxes:

a) Express the total number of boxes as a single power.

b) If each box contains $2^3$ packs of paper, how many packs of paper are there in total in the block? Express the result as a power of base 2.

4 4 4 1 SHELVING UNIT ↳ 4 boxes ↳ 1 box = 2³ pkts.
Solve
Practice★★☆Not started
Work out the value of the following combined expressions respecting the order of operations: a) $2^4 - 3^2 + \sqrt{25} \cdot 2 =$ b) $(5-2)^3 + 10^2 : (2^2 + 1) =$ c)…

Work out the value of the following combined expressions respecting the order of operations:

a) $2^4 - 3^2 + \sqrt{25} \cdot 2 =$

b) $(5-2)^3 + 10^2 : (2^2 + 1) =$

c) $2 \cdot (3^2 - 4) + \sqrt{64} : 2^3 =$

( ) 1st Brackets xⁿ √ 2nd Powers & Roots · : 3rd Mult. & Div. + - 4th Add. & Subtr.
Solve

Finding an unknown exponent

If you can make both sides of an equation have the same base, you can compare the exponents directly.

Three-step procedure for finding an unknown exponent by reducing to powers of base 2 and equating exponents 2ⁿ · 2³ · 2 = 1024 everything in base 2: 2^(n+4) = 2¹⁰ n+4=10 → n=6
Practice★★☆Not started
A video by a streamer has gone viral on a social network. During the first few hours, the number of people sharing the video triples every hour. If 3 people shared it at…

A video by a streamer has gone viral on a social network. During the first few hours, the number of people sharing the video triples every hour. If 3 people shared it at the start:

a) Write as a power the number of people who will have shared the video after 5 hours.

b) Work out the value of this power to find the total number of people at that time.

×3 ×3 ... t = 0 h 3¹ N = 3 t = 1 h 3² N = 9 t = 2 h 3³ N = 27 t = 5 h ? N = ?
Solve
Practice★★★Not started
Find the value of the unknown $n$ in the following equations, applying the laws of indices: a) $2^n \cdot 2^3 \cdot 2 = 1024$ b) $5^6 : 5^n = 125$ c)…

Find the value of the unknown $n$ in the following equations, applying the laws of indices:

  1. a) $2^n \cdot 2^3 \cdot 2 = 1024$
  2. b) $5^6 : 5^n = 125$
  3. c) $(3^2)^n \cdot 9 = 3^{10}$
Solve

Back to the start: The number of people who have shared the video after $5$ hours can be written compactly as $3^5 = 243$.

Summary

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