MATH IN MY WORLD key 5

NGUYỄN TRƯỜNG GIANG PHẠM TRÍ ĐỨC - NGUYỄN TRUNG HIẾU Answer key LET’S GET STARTED Page b b c a b c Unit LET’S PRACTICE Page 10,675; 5,768; 2,955; 13,056 a 13,743; b 3,920 LET’S TRY Page &10 The answer is 9,750 m2 187; 165; the answer is 352 (students) MATH IN MY WORLD Page 10 The answer is 1,250 (pages) Unit Page 11 1,462; 16,692; 47,311; 1,452 234; 2,340; 1,794; 17,940 The answer is 1,800 (times) 273,000; 322,500; the answer is 595,500 (vnd) Unit LET’S PRACTICE Page 12 372; 12; 280; a 258; b 207 LET’S TRY Page 13 The answer is 105 (m) The answer is 16 (sets) MATH IN MY WORLD Page 14 The answer is 42 (m2) Unit Page 15 107; 234; 315; 57 6,240; the answer is 104 (packages) 38,400 m; 75 mins; 0.512 km/min Unit LET’S PRACTICE Page 18 a b 40 cm2; 1,400 cm2; 8,820 cm2 LET’S TRY Page 18 & 19 The answer is 1,000 (dm2) m; the answer is 108 (m2) MATH IN MY WORLD Page 19 parallelograms Unit LET’S PRACTICE Page 20 & 21 Four hundred twenty nine square kilometer; fifty one thousand thirty-four square kilometer; 100,300 km2; 67,000,000 km2 a 1,000,000 m2; b 100 cm2; c 5.25 m2; d km2; e 8,000,000 m2; f 4.05 m2 LET’S TRY Page 21 & 22 3.6 km; 16.2 km2 km; the answer is km2 MATH IN MY WOLRD Page 22 C; C Unit LET’S PRACTICE Page 23 & 24 a ; ; ; b ; ; c ; ; ; LET’S TRY Page 24 a ; b ; c a ; b ; c ; MATH IN MY WORLD less than 1: ; equal to 1: ; greater than 1: d Unit LET’S PRACTICE Page 26 & 27 a ; a = ; ; ; b ; b = = ; LET’S TRY Page 27 = ; = MATH IN MY WORLD ‘a’ is the correct answer 10 Review Page 28 b c b b ; ; ; a 5,000,000 m2; b km2; c 52.64 m2; d 1,000 dm2 Page 29 a 171 cm2; b 206 cm2 a 25 m; b 1,875 kg 11 Unit LET’S PRACTICE Page 32 a and and b a ; and ; and b ; ; LET’S TRY and and ; MATH IN MY WORLD Page 33 > 12 Unit 10 LET’S PRACTICE Page 35 ; ; LET’S TRY Page 35 & 36 The answer is (m) (m) and (m) MATH IN MY WOLRD Page 36 a and b and ; 13 ; Unit 11 LET’S PRACTICE Page 38 a ; b ; c 1; d ; e ; f LET’S TRY 64 (m); 288 (m); 5,120 (m2) MATH IN MY WOLRD Page 39 m2; m2 14 Unit 12 Page 40 a ; a ; b ; c ; b (m) Page 41 a (km2); b (km2) 15 d Unit 13 LET’S PRACTICE Page 43 & 44 a AB is the height; AC is the base b HA is the height; NO is the base a 0.216 cm2; 2.16 m2 LET’S TRY Page 44 2.7 m; 4.86 m2 16 Unit 14 LET’S PRACTICE Page 45 & 46 a AD and BC are two bases; AB and CD are two lateral sides; HB is the height b MN and PQ are two bases; PM and QN are two lateral sides; PM is also the height a 6.9 cm2; b 9,660 cm2 LET’S TRY Page 46 & 47 a Page 47 a 36 (m); b 10,125 (kg) 17 b Unit 15 LET’S PRACTICE Page 48 a 7.85 cm; b 8.164 cm LET’S TRY Page 49 282.6 cm 18.84 cm; 37.68 cm 18 Unit 16 LET’S PRACTICE Page 50 a 4.5216 cm2; b 0.5 dm; 0.785 dm2 1.5 m; 7.065 m2 LET’S TRY Page 51 cm; 28.26 cm2 36 cm2; 7.74 cm2 MATH IN MY WORLD Page 51 & 52 1.5386 m2; m; 3.14 m2; 1.6014 m2 19 Review Page 53 a ; b ; (m2) Page 54 C = 3.768 dm, S = 1.1304 dm2 The difference is 125.6 cm Page 55 a T; b F 20 c ; d ; ... Page 10,6 75; 5, 768; 2, 955 ; 13, 056 a 13,743; b 3,920 LET’S TRY Page &10 The answer is 9, 750 m2 187; 1 65; the answer is 352 (students) MATH IN MY WORLD Page 10 The answer is 1, 250 (pages)... answer is 1 05 (m) The answer is 16 (sets) MATH IN MY WORLD Page 14 The answer is 42 (m2) Unit Page 15 107; 234; 3 15; 57 6,240; the answer is 104 (packages) 38,400 m; 75 mins; 0 .51 2 km/min Unit... dm2 1 .5 m; 7.0 65 m2 LET’S TRY Page 51 cm; 28.26 cm2 36 cm2; 7.74 cm2 MATH IN MY WORLD Page 51 & 52 1 .53 86 m2; m; 3.14 m2; 1.6014 m2 19 Review Page 53 a ; b ; (m2) Page 54 C = 3.768 dm,