Exercise (4.4)
(b)(1.1  0.8)  0.4  0.3  0.4
 0.12
(1)(a)(0.3  0.4)  0.2  0.7  0.2
 0.14
(2) (a) 0.48
(b) 0.6
(c) 0.24
(3)(a)52  0.9  52(1  0.1)
 52  1  52  0.1
 52  5.2
 46.8
(4)(a) 25.2
(b)15.3
(d) 0.33
(b)8.3  0.9  8.3  (1  0.1)
 8.3  0.83
 7.47
(c)4.41
(5) (a)(b) learners’ answers
(c)(i)26  9.9  257.4
(ii )26  0.99  25.74
(6) area of the rectangle
 width  height
 6  9.9
 6  (10  0.1)
 6  10  6  0.1
 60  0.6
 59.4m 2
(7) the patients the new medicine made better
 3200  0.99 (99%  0.99)
 3168
(8)(a)2.5  32.7  4  2.5  4  32.7
 10  32.7
 327
(c) 546
(d) 26.4
(e) 42
(b)
0.2  2.3 0.2  2.3  10 2  2.3


 4.6
0.1
0.1 10
1
(9)(a)24  0.35  24  0.5  0.7
 12  0.7
 12  7  10
 84  10
 8.4
(10)(a) 12
(b)32  0.45  32  0.5  0.9
 16  0.9
 16  9  10
 144  10
 14.4
(b) 29
11(a) 25.2 (use 0.14  0.2  0.7 )
(b) 19.2 (use 0.16  0.4  0.4 )
(c) 45 (use 0.18  0.2  0.9 )
(d) 108 (use 0.24  0.6  0.4 )
(12) learners’ answers
(13) Abdul gets 12600  0.35  $4410 . Zhi gets 12600  0.25  $3150 . Paula gets
12600  0.22  $2772 and Yola gets 12600  0.18  $2268 .
(b) 4410  3150  2772  2268  12600
(14) Sofia is correct.
32  (0.8  0.4) 32  0.4 32  0.4  100 32  40



 32  20  640  800
0.02
0.02
0.02  100
2
32  (0.8  0.3) 32  0.5 32  0.5  100 32  50



 16  50  800
0.02
0.02
0.02  100
2
So the missing number is 0.3.