Question

Calculează : a) suma numerelor 3,72 și 2,22 b) numărul de 100 de ori mai mic decât 258 c) 2/7 × 14/10 + 4/9:10/9 + 5^2/ 5^3 d) (1/2-1/8) × 2^4 e) 1/201+2/201+... +201/201 f) (1+1,8^2×100):(2,4×15-0,1^3 × 1000 × 11) g) 5,2 + 5, (2)-5,02-5,0(2)

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Answer 1

a) 3,72 + 2,22 = 5,94

b) 258:100 = 2,58

c) 2/7 x 14/10 + 4/9:10/9 + 5²/5³ = 2/5 + 4/9 x 9/10 + 1/5 = 3/5 + 2/5 = 5/5 = 1

d) (1/2 - 1/8) x 2⁴ amplific 1/2 cu 4

(4/8 - 1/8) x 16 = 3/8 x 16 = 3 x 2 = 6

e) 1/201 + 2/201 + ......+ 201/201 = (1+2+3+.....+201)/201 = S/201

S (suma lui Gauss) = [(1+201)x201]/2 = [202x201]/2 = 101x201

(101x201)/201 = 101

f) (1 + 1,8² x 100):(2,4 x 15 - 0,1³ x 1000 x 11) = (1 + 3,24 x 100):(36 - 0,001 x 1000 x 11) = (1 + 324):(36 - 11) = 325:25 = 13

g) 5,2 + 5,(2) - 5,02 - 5,0(2) =

52/10 + 47/9 - 502/100 - 452/90 amplific pe 52/10 si pe 47/9cu 10 =

(520-502)/100 + (470-452)/90 = 18/100 + 18/90 = 9/50 + 1/5 amplific pe 1/5 cu 10

9/50 + 10/50 = 19/50