Four students each write the number 84000 in standard form.
Amir writes 8.4 x 104 Ben writes 84 x 103 Chloe writes 0.84 x 105 Dev writes 8.4 x 103
Exactly one student has written the number correctly in standard form. Write down the name of that student.
(Total for Question 5 is 1 mark)
6
Write the number 0.0000059 in standard form.
(Total for Question 6 is 1 mark)
7
Write 7.2 x 10-4 as an ordinary number.
(Total for Question 7 is 1 mark)
8
Write 3.15 x 106 as an ordinary number.
(Total for Question 8 is 1 mark)
9
Which is larger, 6.4 x 103 or 5.9 x 104? Write down the larger number, in standard form.
(Total for Question 9 is 1 mark)
10
Here are four numbers written in standard form.
7.1 x 102 6 x 103 8.4 x 101 2.3 x 103
Put the numbers in order of size, starting with the smallest.
(Total for Question 10 is 2 marks)
11
Write the number 0.000000083 in standard form.
(Total for Question 11 is 1 mark)
12
Write 4 x 10-1 as an ordinary number.
(Total for Question 12 is 1 mark)
13
Work out (3 x 104) x (2 x 103). Give your answer in standard form.
(Total for Question 13 is 2 marks)
14
Work out (9 x 107) / (3 x 102). Give your answer in standard form.
(Total for Question 14 is 2 marks)
15
Work out (4 x 105) x (5 x 103). Give your answer in standard form.
(Total for Question 15 is 2 marks)
16
Work out (6 x 102) / (1.5 x 10-3). Give your answer in standard form.
(Total for Question 16 is 2 marks)
17
A bacterium has a diameter of 4 x 10-6 m. A dust mite has a diameter of 2 x 10-4 m. Work out how many times bigger the diameter of the dust mite is than the diameter of the bacterium.
(Total for Question 17 is 3 marks)
18
Work out (5.4 x 105) + (6 x 104). Give your answer in standard form.
(Total for Question 18 is 3 marks)
19
A scientist collects a sample of fine sand. Each grain of sand has a mass of 4 x 10-4 g. The sample contains 5 x 106 grains of sand.
(a)Work out the total mass of the sample. Give your answer, in grams, in standard form.(3)
(b)Given that 1 kg = 1000 g, work out the total mass of the sample in kg.(2)
(Total for Question 19 is 5 marks)
20
Three stars have these distances from Earth, in light-years.
Star P: 3.6 x 102 Star Q: 9 x 101 Star R: 1.4 x 103
Put the stars in order of distance from Earth, starting with the nearest. Show how you have compared the distances.
(Total for Question 20 is 2 marks)
21
The wavelength of a particular red light is 6.5 x 10-7 m. The wavelength of a particular radio wave is 1.3 x 101 m. Work out how many times longer the wavelength of the radio wave is than the wavelength of the red light. Give your answer in standard form.
(Total for Question 21 is 3 marks)
22
(4 x 10n) x (2 x 103) = 8 x 108
Find the value of n.
(Total for Question 22 is 2 marks)
23
A pupil says that 0.00038 is equal to 38 x 10-5 written in standard form. A second pupil says the first pupil is wrong, and that the correct standard form is 3.8 x 10-4. By writing both expressions as ordinary numbers, determine which pupil (if either) is correct, and explain any error in the incorrect statement.
(Total for Question 23 is 3 marks)
24
M2 = 4 x 1010, where M > 0. Find the value of M. Give your answer in standard form.
(Total for Question 24 is 3 marks)
25
Solve the equation (5 x 10n)2 = 2.5 x 1015, where n is an integer.
(Total for Question 25 is 3 marks)
Mark scheme · 5.4D Standard Form: Fluency and Exam Drill
Question 1
B1 6.8 x 104 oe
Answer: 6.8 x 104
Question 2
B1 4.7 x 10-5 oe
Answer: 4.7 x 10-5
Question 3
B1 91000 cao
Answer: 91000
Question 4
B1 0.00206 cao
Answer: 0.00206
Question 5
B1 Amir
Answer: Amir (8.4 x 104 is correctly in standard form, since 1 ≤ 8.4 < 10, and 8.4 x 104 = 84000)
Question 6
B1 5.9 x 10-6 oe
Answer: 5.9 x 10-6
Question 7
B1 0.00072 cao
Answer: 0.00072
Question 8
B1 3150000 cao
Answer: 3150000
Question 9
B1 5.9 x 104 oe (59000)
Answer: 5.9 x 104
Question 10
M1 converts numbers to a comparable form, e.g. as ordinary numbers 84, 710, 2300, 6000 oe
A1 8.4 x 101, 7.1 x 102, 2.3 x 103, 6 x 103 cao, all four in correct order
Answer: 8.4 x 101, 7.1 x 102, 2.3 x 103, 6 x 103
Question 11
B1 8.3 x 10-8 oe
Answer: 8.3 x 10-8
Question 12
B1 0.4 cao
Answer: 0.4
Question 13
M1 3 x 2 = 6 and 104 x 103 = 107 seen, or 6 x 107 oe unsimplified
A1 6 x 107 cao
Answer: 6 x 107
Question 14
M1 9 / 3 = 3 and 107 / 102 = 105 seen, or 3 x 105 oe unsimplified
A1 3 x 105 cao
Answer: 3 x 105
Question 15
M1 4 x 5 = 20 and 105 x 103 = 108 seen, or 20 x 108 oe unsimplified
A1 2 x 109 cao (converts 20 x 108 to correct standard form)
Answer: 2 x 109
Question 16
M1 6 / 1.5 = 4 and 102 / 10-3 = 105 seen, or 4 x 105 oe unsimplified
A1 4 x 105 cao
Answer: 4 x 105
Question 17
M1 sets up (2 x 10-4) / (4 x 10-6)
M1 2 / 4 = 0.5 and 10-4 / 10-6 = 102 seen, or 0.5 x 102 oe unsimplified
A1 50 cao
Answer: 50 (times bigger)
Question 18
M1 writes both numbers to the same power of 10, e.g. 54 x 104 + 6 x 104 oe
M1 dependent, adds correctly to give 60 x 104 oe
A1 6 x 105 cao
Answer: 6 x 105
Question 19
(a) M1 multiplies coefficients, 4 x 5 = 20
(a) M1 dependent, adds powers of 10, -4 + 6 = 2, giving 20 x 102
(a) A1 2 x 103 cao (g)
(a) Answer: 2 x 103 g
(b) M1 ft, divides their part (a) answer by 1000, e.g. (2 x 103) / (1 x 103)
(b) A1 ft, 2 cao (kg)
(b) Answer: 2 kg
Question 20
M1 converts distances to a comparable form, e.g. as ordinary numbers 360, 90, 1400 oe
A1 Q, P, R cao, all three in correct order (nearest first)
Answer: Star Q, Star P, Star R
Question 21
M1 sets up (1.3 x 101) / (6.5 x 10-7)
M1 1.3 / 6.5 = 0.2 and 101 / 10-7 = 108 seen, or 0.2 x 108 oe unsimplified
A1 2 x 107 cao
Answer: 2 x 107
Question 22
M1 multiplies coefficients, 4 x 2 = 8, matching the given coefficient, so equates powers of 10, giving n + 3 = 8
A1 n = 5 cao
Answer: n = 5
Question 23
M1 converts 38 x 10-5 and/or 3.8 x 10-4 to an ordinary number, showing both equal 0.00038
B1 states the second pupil is correct
B1 dependent on M1, explains that although 38 x 10-5 is numerically equal to 0.00038, it is not in standard form because 38 is not between 1 and 10, whereas 3.8 x 10-4 is correctly in standard form because 3.8 is between 1 and 10
Answer: The second pupil is correct; 3.8 x 10-4 is the correctly written standard form of 0.00038.
Question 24
M1 finds the square root of the coefficient, √4 = 2
M1 finds the square root of the power of 10, √1010 = 105, e.g. by writing 1010 as (105)2
A1 2 x 105 cao
Answer: M = 2 x 105
Question 25
M1 squares the left-hand side, (5 x 10n)2 = 25 x 102n oe unsimplified
M1 dependent, converts to standard form and equates powers, 25 x 102n = 2.5 x 102n + 1, so 2n + 1 = 15