Transcript Practice 3

GCSE
Mathematics
Targeting Grade C
Number
Unit 3 Long Multiplication
Division and Estimation
Can you:
If not you need
TOP 1: Review 1 - some
multiplication/division
•Solve long multiplication
Practice 1: Long multiplication
•Solve problems with division
Practice 2: Division problems
Try a Quick Test
•Estimate solutions
•Round to a given number of significant
figures or decimal places
Try a Quick Test
TAIL 1
TOP 2: Review 2 – rounding to
significant figures and decimal
places
Practice 3: Estimating values and
rounding solutions
TAIL 2
TOP 1: Solve
(1)
27  7
(2)
66  3
(3)
752  11
(4)
12  243
(5)
145  5
(6)
291  3
(7)
126  4
(8)
468  8
Lesson
Practice 1:
Solve the following, showing all your working.
(1)
156  15
(a)
..........................…(3)
(b)
237  24
..........................…(3)
(c)
753  63
..........................…(3)
Solve these problem, showing your working.
(2)
(a) Tom buys 67 cameras at £312 each. Work out the total
cost.
................................
(3)
(b) Carol spends £2.80 on each of her class. She has 25 students.
How much does she spend in total?
.......................................
Lesson
(3)
Practice 2:
Solve the following, showing all your working.
(1) (a)
356  24
(b)
835  27
(c)
423  19
………………………
(3)
...…………………….
(3)
………………………
(3)
Solve these problems, showing your working.
(2) (a) Tim paid £5.44 for 17 pencils. Each pencil costs the same.
Work out the cost of each pencil.
………………………
(3)
(b)
Sophie has £126 to share between her 16 friends. How much do
they each get?
………………………
(3)
Lesson
TAIL 1
Mrs. Evans decides to take 863 students on a trip to Euro Disney. They
travel by coach.
Each coach can hold up to 51 students.
In this part of the question you MUST NOT use a calculator. You MUST
show ALL your working
(a) Work out the smallest number of coaches Mrs. Evans should book so
that all the students can go on the trip.
(3 marks)
Each student has to pay £37 for the trip. 745 students decide to go on the
trip.
In this part of the question you MUST NOT use a calculator. You MUST
show ALL your working
(b) How much money is collected if all 745 students pay £37 each.
(3 marks)
Are you ready for
the answers ?
Next
Answers
(a) 863  51 = 16 r 47, so 17 coaches.
(b) 745  37 = £27 565
Lesson
TOP 2:
Round the following to the number of decimal places given in the brackets.
(1) 15.645 (2 d.p.)
(2)
18.756 (1 d.p.)
(3)
65.95 (1 d.p.)
(4)
99.997 (2 d.p.)
Round the following to the number of significant figures given in the
brackets.
(1) 26.4 (1 s.f.)
(2)
164.8 (2 s.f.)
(3)
87.954 (3 s.f.)
(4)
0.00346 (2 s.f.)
Lesson
Practice 3: By using approximation answer the following
questions:
(1)
Tom buys 67 cameras at £312 each.
Write down two numbers you could use to get an approximate
answer to your calculation.
(2)
Tom uses his calculator to multiply 17.8 by 0.97. His answer is
18.236.
Without finding the exact value of 17.8  0.97, explain why his
answer must be wrong.
(3)
Sally estimates the value of 42.8  63.7
285
to be 8.
Write down three numbers Sally could use to get her estimate.
…………  …………
…………
Lesson
Are you ready for the answers?
TAIL 2
240
80  3
1
0.000727
2 Write 0.000 726 9 correct to 3 s.f.
48
96  2
3
4
Write 37 451 correct to 1 s.f.
40 000
215  5
5
43
195
65  3
6
Write 12.564 correct to 2 d.p.
12.56
7
9888
412  24
8
45 r 14
734  16
9
Write 15.9504 correct to 3 d.p.
15.950
10
Lesson