焦瑞
I. Calculation.
(1) 2.25 × 3 =
(2) 1.60 × 15 =
(3) 40.07 × 3.2 =
(4) 63 ÷ 2.5 =
(5) 9.6 ÷ 0.4 =
(6) 4.8 ÷ 1.2 =
II. Calculate and round to one decimal place.
(1) 3.4 × 1.7 ≈
(2) 2.25 × 0.4 ≈
(3) 1.2 × 3.6≈
(4) 2.3 × 4.6 ≈
(5) 3.5 ÷ 2.1 ≈
(6) 8.77 ÷ 0.3 ≈
III. Make verticals.
(1) 30.605 × 43 =
(2) 203.06 × 15.25 =
(3) 80.4272 ÷ 12.04 =
(4) 1805.804 ÷ 50.05 =
IV. Fill in the blanks.
(1) 0.8 × _____ = 2.4
(2) 9.5 ÷ _____ = 2.375
(3) 5.2 × _____ = 15.6
(4) _____ ÷ 5 = 3.6
(5) _____ × 3 = 6.9
(6) 145.92 ÷ _____ = 2.4
(7) 12.6 ÷ _____ = 4.2
(8) _____ ÷ 7.08 = 4.3
V. Word problems.
(1)A box of chocolates costs $4.50, and Sarah buys 3 boxes. How much does she spend in total?
(2)A book costs $12.25, and Emma buys 2 books. How much does she pay?
(3)Susan earns $8.50 per hour, and she works 5.5 hours in a day. How much does she earn for the day?
(4)There are 9.6 feet of ribbon, and Emma wants to cut pieces that are 0.4 feet long. How many pieces can she cut?
(5)Susan has $18, and she wants to buy 2 packs of markers, each costing $3.75. Can she afford them?
(6)If a pizza with a diameter of 50 cm is divided into 8 equal slices, how long is each slice?
(7)Emma walks her dog 2.5 km every day. How many kilometres will she walk in a week?
(8)Lisa has a rectangular garden that is 6.3 m wide and 8.4 m long. What is the area of her garden in square feet?
Keys to Intensive Training of Decimals (5A)
I. (1) 6.75 (2) 24 (3) 128.224 (4) 25.2 (5) 24 (6) 4
II. (1) 5.8 (2) 0.9 (3) 4.3 (4) 10.6 (5) 1.7 (6) 29.2
III. (1) 1316.015 (2) 3096.665 (3) 6.68 (4) 36.08
IV. (1) 3 (2) 4 (3) 3 (4) 18 (5) 2.3 (6) 60.8 (7) 3 (8) 30.444
V. (1) 13.50 (2) 24.50 (3) 46.75 (4) 24 (5) Yes, she can. Because 2 packs of
markers cost 7.5 dollars only. (6) 6.25 (7) 17.5 km. (8) 52.92 m2.