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Revision IGCSE Unit A Ex. A Without using a calculator, evaluate the expression given in questions 1 – 8.
1.) 4 + 5× 3−11 2.) 11− 324
3.) 30 ÷ 5+ 20 ÷ 2 4.) 5× 6 ÷ 3÷ 2 −1
5.) 10 + 2 × 11− 5( ) 6.) 10 × 11− 5( )32 + 3
7.)
105− 3× 3
11−12 8.)
12+ 13
1214
× 715
Use your calculator to find the value of each of the following, giving your answer to 3 s.f.
9.) 9.13 − 9.13 10.) 13− 9.84.2 × 4.1
11.) 5π4 12.) 4.6 −1.3 1.9 −1.1( )2( )−1 13.) log3 7
1.3−1.22 14.) 3 7.8+ 9.3− log4 5( )0.5⎡
⎣⎤⎦ 15.)
3× sin23º302 −16
16.) 25!7
Ex. B Find the value of each of the following (no calculators allowed).
1.) 52 2.) 5–2 3.) 50 4.) 3612 5.) 8
23 6.) 8
−23
7.) 71 8.) 100–32 9.) 27
43 10.) 72 × 2−1 11.) 64
–12 × 42 12.) 50 × 41 × 32 × 23 ×14
Ex. C Simplify each of the following.
1.) m3 ×m4 ×m 2.) 5y4 × 4y5 3.) p6
p3 4.) 10p
16
2p2 5.) k 4( )−3
6.) 3g4( )2 7.) 50m14 ÷ 25m3 8.) d13 × dd3( )−2
9.) n2m3 × nm4
n5m6 10.) 3t3 × 2t5 × t( )3
11.) 4e3h4( )2 ÷8e−4h( )6 12.) 25t8 13.) 27p123 × 4p−4q2
14.) Without using a calculator, find the value of: 47 × 43
48⎛⎝⎜
⎞⎠⎟
−1
Ex. D In questions 1 – 6 write the number in standard form. 1.) 35000 2.) 4000000 3.) 0.000132 4.) 0.00000000009 5.) 88888900 6.) 0.1235 For questions 7 – 12 write each as an ordinary number. 7.) 5.12 ×103 8.) 1.4 ×10−3 9.) 7×106 10.) 8.8×100 11.) 9.909 ×10−5 12.) 1.3657×107 13.) Juan Carlos has 6 million jelly beans. Write the number of jelly beans he as in standard form. 14.) María Jesús collects ants. She has 2½ thousand ants. Write the number of ants she has in standard form. 15.) Write each of the following in standard form. (a.) 12.3×105 (b.) 0.006 ×1023 16.) A googol is the digit 1 followed by one hundred zeroes (i.e. 1000000…). Write 12 googol in standard form.
Ex. E Find the answers to questions (1.) – (6.) using a calculator. Give answers in standard form, rounding to 3 s.f.
1.) 2.15 ×1013 + 5.89 ×1014 2.) 9.12 ×10–14( )× 1.1×1056( ) 3.) 5.2 ×10−4
3.81×10−20
4.) Light travels at 3×108 m/s. Calculate the time it takes light to travel 3 cm.
5.) The base of a microchip is in the shape of a rectangle. Its length is 2 ×10−3 mm and its width is 1.55×10−3 mm. Find the area of the base.
6.) An atomic particle has a lifetime of 3.86 ×10−5 seconds. It travels at a speed of 4.2 ×106 metres per second. Calculate the distance it travels in its lifetime. Find the answers to questions (7.) – (14.) without using a calculator. Give your answers in standard form. 7.) 5.2 ×103( )+ 4.822 ×105( ) 8.) 3.6 ×10−5( )− 3.6 ×10−4( )
9.) 9 ×1013( )× 2 ×1017( ) 10.) 1.5×10−3( )÷ 3×10−7( ) 11.) Let a =5×10−3 . Find the value of a3.
12.) Dario has 1.95×1013 frogs, and Jorge has 2.81×1014 frogs. How many frogs are there altogether?
13.) Daniela can run very fast! She runs at an average speed of 5×105 metres per second. The length of the coastline in the UK is 9000km. Daniela decides to run round the coastline – how long will it take her?
14.) If each of Jorge’s frogs weighs 4g, what is the total weight of his frogs. Give your answer in kilograms. Ex. F In questions 1 – 14 find the value of each expression – no calculators!
1.) log10100 2.) log3 27 3.) log616
⎛⎝⎜
⎞⎠⎟ 4.) log9 9 5.) log8 2 6.) log2 2 7.) log3
181
⎛⎝⎜
⎞⎠⎟
8.) log101 9.) log2 32 10.) log51125⎛⎝⎜
⎞⎠⎟ 11.) log125 5 12.) loga a
3 13.) log10 0.01 14.) log6 6 6
In questions 15 – 21 use your calculator to find the value of the expression. 15.) log310 16.) log10 3 17.) log5100000 18.) log12 0.8 19.) log9 99 20.) log6 216 21.) log7 7.1 Ex. G 1.) Write each of the following as a single logarithm. a.) log8+ log3 b.) log6 − log2 c.) 2 log3 d.) log5+ log4 − log2 e.) 2 log7+ 3log2
f.) log 25
⎛⎝⎜
⎞⎠⎟ + log10 g.) 1
3log 1
8⎛⎝⎜
⎞⎠⎟
2.) Simplify each of the following expressions. a.) log x + log y b.) 10 log x c.) log x − log y d.) log5x − log10y e.) 2 log6x − log18x 3.) Let a = log4 , b = log5 and c = log3 . Write each of the following in terms of a, b and c.
a.) log20 b.) log 45
⎛⎝⎜
⎞⎠⎟ c.) log25 d.) log75 e.) log80
4.) Let p = log x , q = log y and r = log z . Write each of following in terms of p, q and r.
a.) log xyz b.) log x2
y⎛⎝⎜
⎞⎠⎟ c.) log x3z4( ) d.) 5log z3
xy⎛⎝⎜
⎞⎠⎟
Ex. H Solve each of the following equations, giving your answer to 3 s.f. where appropriate. 1.) 2x =10 2.) 3x =17 3.) π x =10 4.) 5× 2x = 26 5.) 33x = 21
6.) 125x = 14 7.) 22 x = 4096 8.) 3
4⎛⎝⎜
⎞⎠⎟x
=10−3 9.) 300 × 20.005x =1000 10.) 4x−1 =100
11.) The weight W grams, of a sample of radioactive uranium remaining after t years is given by the formula W = 500 × 2−0.0002t grams. Find the time taken for the weight of the sample to become 200 grams.
12.) The current I amps in a radio, t seconds after it is switched off is given by I = 4 × 2−0.02t amps. Find the time taken for the current to be 1 amp.
Ex. I 1.) Simplify each of the following. a.) 8 b.) 20 c.) 27 d.) 5 12 e.) 300 + 75 f.) 5 8 + 7 500 − 2 18 g.) 3 2 + 3( ) h.) 3 +1( ) 2 + 3( ) i.) 10 2 + 5( ) j.) 5 −1( ) 2 + 5( ) k.) 2 − 3( )2 l.) 6 + 10( ) 15 − 3( ) 2.) In each of the following find the value of k. a.) 800 = k 2 b.) −3 80 = k 5 3.) A rectangle has a length of 7+ 2( ) cm and a width of 3+ 8( ) cm. Find the area and the perimeter of the rectangle, giving your answers exactly. 4.) The lengths of the two shorter sides of a right-‐angled triangle are 7 cm and 2 cm. Find the length of the longest side of the triangle. 5.) Rationalise the denominator for each of the following.
a.) 12 b.) 1
6 c.) 2
7 d.) 3
5 e.) 2
3 11 f.) 10
3 5 g.) 2
5
h.) 6 72 3
i.) 26 j.) 3 +1
2 k.) 2 + 3
6 l.) 1
4 + 3 m.) 3
2 − 7 n.) 4 + 3
1+ 5
o.) 2 + 32 − 5
p.) 714 + 7
q.) 1− 63+ 2 3
6.) The area of a rectangle is 7 cm. If the width is 2 cm, what is the length of the rectangle? Give your answer exactly. 7.) Cata runs a very unusual race. The track is exactly 50 + 2 metres long. Cata runs the race in exactly 10 − 7( ) seconds. What was Cata’s speed during the race. Give your answer exactly.
Answers ***Watch out – there are bound to be mistakes*** Ex. A 1.) 8 2.) ½ 3.) 16 4.) 4 5.) 22 6.) 5 7.) 7 8.) 2512 9.) 751 10.) 0.186 11.) 1.99 12.) 0.265 13.) –12.7 14.) 32.0 15.) 0.0394 16.) 2.22 ×1024 Ex. B 1.) 25 2.) 125 3.) 1 4.) 6 5.) 4 6.) ¼ 7.) 7 8.) 1
1000 9.) 81 10.) 492 = 24½ 11.) 2 12.) 288 Ex. C 1.) m8 2.) 20y9 3.) p3 4.) 5p14 5.) k–12 6.) 9g8 7.) 2m11 8.)d20 9.) n–2m 10.) 216t27 11.) 64e60h42 12.) 5t4 13.) 12q2 14.) 116 Ex. D 1.) 3.5 × 104 2.) 4 × 106 3.) 1.32 × 10–4 4.) 9 × 10–11 5.) 8.88889 × 107 6.) 1.235 × 10–1 7.) 5120 8.) 0.0014 9.) 7000000 10.) 8.8 11.) 0.0000909 12.) 13657000 13.) 6 × 106 14.) 2.5 × 10–3 15a.) 1.23 × 106 b.) 6 × 1020 16.) 1.2 × 10101 Ex. E 1.) 6.105 × 1014 2.) 1.0032 × 1043 3.) 1.36 × 1016 4.) 1 × 10–8 seconds 5.) 3.1 × 10-‐6 6.) 1.62 × 102 7.) 4.874 × 105 8.) –3.24 × 10–4 9.) 1.8 × 1031 10.) 5 × 103 11.) 1.25 × 10–7 12.) 3.005 × 1014 13.) 18 seconds 14.) 1.124 × 1012 Ex. F 1.) 2 2.) 3 3.) –1 4.) 1 5.) 13 6.) ½ 7.) –4 8.) 0 9.) 5 10.) –3 11.) 13 12.) 3 13.) –2 14.) 32 15.) 2.10 16.) 0.477 17.) 7.15 18.) –0.898 19.) 2.09 20.) 3 21.) 1.01 Ex. G 1a.) log24 b.) log3 c.) log9 d.) log 10 e.) log392 f.) log4 g.) log(½) 2a) logxy b.) logx10 c.) log( x
y ) d.) log( x2y ) e.) log2x
3a.) a + b b.) a – b c.) 2b d.) 2b + c e.) 2a + b 4a.) p + q + r b.) 2p – q c.) 3p + 4r d.) 15r – 5p – 5q Ex. H 1.) 3.32 2.) 2.58 3.) 2.01 4.) 2.38 5.) 0.924 6.) –0.112 7.) 6 8.) 24.0 9.) 3470 10.) 4.32 11.) 6610 years 12.) 100 seconds Ex. I 1a.) 2√2 b.) 2√5 c.) 3√3 d.) 10√3 e.) 15√3 f.) 70√5 + 4√2 g.) 2√3 + 3 h.) 5 + 3√3 i) 2√5+5√2 j.) 3 + √5 k.) 7 – 4√3 l.) 3√10 – 3√2 + 5√6 – √30 2a.) 20 b.) –12 3.) Area = 25 + 17√2 Perimeter = 20 + 6√2 4.) 3 5a.) 2
2 b.) 66 c.) 2 7
7 d.) 3 55 e.) 2 11
33 f.) 2 53 g.) 10
5
h.) √21 i.) 63 j.) 6+ 2
2 k.) 3 2+2 36 l.) 4− 3
13 m.) –2 – √7 n.) 4−4 3+ 3− 15−4
o.) 2+ 10+ 6+ 15−3 p.) −1+2 7
27 q.) 3−2 3−3 6+6 2−3
6.) 142 7.) 20 2+2 14
31