I. Calculate.

50.25+3.46=""" 2.67+6.88=""" 75×0.5=

5.09-4.42=""" 10.11-9.97=""" 10.442會(huì)9.08=

7.2×100=""" 0.005×1000=""" 3.5×6.6=

29.664÷8.24=""" 3.034÷0.05=""" 0.076÷0.25=

4.25×14+7.6-5.25÷0.5""" (5.18+6.07)÷12.5×(3.3÷0.6)

=" " " " " " " " " " " " " " " " " =

=" " " " " " " " " " " " " " " " "=

75.75÷(0.125×20.2)×(9.06-7.8)"" "9.43+66.6÷0.222×0.43-108.64

=" " " " " " " " " " " " " " " " " " " " " " " =

=" " " " " " " " " " " " " " " " " " " " " " " =

=" " " " " " " " " " " " " " " " " " " " " " " =

II. Fill in the blanks.

(1) 723 cm =________m.

(2) The digit in the tenth value place of the number 109.38 is ________.

(3) There are________hundredth in the number 9214.038.

(4)________is 0.03 more than 12.44.

(5) The value of the underlined digit in 38.437 is________.

(6) If one pencil box costs 9.50 yuan， the cost of 5 pencil box is ________.

(7) Round 300.075 to the nearest whole number. 300.075 ≈________.

(8) 1.243 is________greater than 1.24 and________less than 1.25.

(9) The length of a rectangle is 16 dm， and its width is 22 dm. The area of the rectangle is________dm².

(10) The value of 20.356÷15 ≈________when rounded to 2 decimal places.

(11) 1， 2， 3 and 6 are the factors of ________.

(12) The lowest common multiple of 32 and 40 is________.

(13)Δ÷30 = 216， so Δ=________.

(14) The perimeter of a rectangle is 26 cm， and the length is 7 cm. The width is________cm.

(15) In △ABC， ∠A = 45°， ∠B = ∠A. The degree of ∠C is ________°.

III. True(√) or 1(×)? Read and judge.

(1) 0， 1， 2， 3， 4， 5， 6， 7， 8， 9， 10， and 11 are natural numbers.()

(2) -5， -4， -3， -2， -1， 0，1，2， 3，4， and 5 are integer numbers.(""" )

(3) 1， 2， 3， 4， 5， 6， 7， 8， 9， 10， and 11 are positive numbers.(""" )

(4) -1， -2， -3， -4， -5， -6， ... are negative numbers.(""" )

(6) 0.1， 0.38， 1.64， and 7.83 are fractions.()

(7) 1， 3， 5， 7， 9， 11， 13， and 15 are odd numbers.()

(8) 2， 4， 6， 8， 10， 12， and 14 are even numbers.()

IV. Circle the correct option， A， B， C or D.

(1) If one eraser costs ￥0.99， the cost of 8 erasers is________.

A. ￥8.99""" B. ￥1.07""" C. ￥7.92""" D. ￥0.91

(2) Multiply 40.026 by 5. The product is________.

A. 20.130""" B. 200.13""" C. 2.13""" D. 20.13

(3) 40.106 is________when rounded to the nearest 2 decimal places.

A. 40.10""" B. 40.1""" C.""" 40.11""" D. 40.2

(4) 35.509 is________when rounded to the nearest 2 decimal places.

A. 35.5""" B. 35.51""" C.""" 355.1""" D. 3.55

(5) The length of a rectangle is 20 cm. The area of the rectangle is 1060 cm². The width of the rectangle is________cm.

A. 1040""" B. 14""" C.""" 21200""" D. 53

(6) The width of a rectangle is 28 m. The perimeter of the rectan-gle is 136 m. The area of the rectangle is________m².

A. 1040""" B. 14""" C. 1120""" D. 53

(7) 9 + (3 + 4) = 16， so， (9 + 3) + 4 =________.

A. 26""" B. 9""" C. 17""" D. 16

(8) What is the missing number? 2 + ( □+ 4) = (2 + 6) + 4.

A. 4""" B. 7""" C. 8""" D. 6

(9) The lowest common multiple of 32 and 40 is________.

A. 320""" B. 160""" C. 120""" D. 80

(10) Find the highest common factor of 48， 54 and 72.

A. 6""" B. 18""" C. 24""" D. 12

V. Solve the problems.

(1) One sandwich costs ￥6.45. How many sandwiches can Jenny buy for ￥40.5? How much change can she get?

(2) Find the shaded area of the parallelogram.

(3) The total weight of 18 oranges and 4 pears is 5.84 kg. If each pear weighs 0.38 kg， what is the average weight of the 18 oranges?

(4) A light flashes every 4 minutes and a bell rings every 5 minutes. If the light flashes as the bell rings at the same time， how long will it be until this happens again?

(5) Jack is 9 years old and his mother is 39 years old now. In how many years， will his mothers's age be twice Jack's age?

(6) In the rectangle ABCD， there is a square EFGD. The area of the shaded part is 90 cm². AE = 8 cm， and CG = 3 cm. Find the area of the square EFGD.

Keys to Self-test of Maths(5A)

IV. (1)~(5) CBCBD""" (6)~(10) CDDAA

V. (1) 6 sandwiches， ￥1.8""" (2) 24 cm²""" (3) 0.24kg

(4) 20 minutes""" (5) 21 years""" (6) 6 cm