Question

[Xfeccy]

a) 4,1×3,5+4,1×7,5-4,1

b) 1/1998 × 2/7 + 1/1998 × 1 và 3/7 - 5/1998 × 1/7

k) [( 2/139 - 3/386)× 139/17 + 33/34] : [(7/2001 + 11/4002) × 201/25 + 9/2]

Answer 1

[Quách Ngọc]

a)4,1×3,5+4,1×7,5-4,1

= 4,1 x ( 3,5 + 7,5 ) - 4,1

= 4, 1x 11 - 4,1

= 45,1 - 4,1

= 41

b) 1/1998 × 2/7 + 1/1998 × 1

= 1/1998 x ( 2/7 + 1 )

= 1/1998 x 9/7

= 1/1554

3/7 - 5/1998 × 1/7

= 3/7 - 5/13986

= 5989/13986

k) [( 2/139 - 3/386)× 139/17 + 33/34] : [(7/2001 + 11/4002) × 201/25 + 9/2]

= [ 355/53654 x 139/17 + 33/34 ] : [ 25/4002 x 201/25 + 9/2 ]

= [ 355/6562 + 33/34 ] : [ 67/1334 + 9/2 ]

= 3362/3281 : 3035/667

= 0,2251949344

Answer 2

[Vũ Minh Tuấn]

a) \(4,1.3,5+4,1.7,5-4,1\)

= \(4,1.\left(3,5+7,5\right)-4,1\)

= \(4,1.11-4,1\)

= \(45,1-4,1\)

= \(41\).

b) \(\frac{1}{1998}.\frac{2}{7}+\frac{1}{1998}.1\)

= \(\frac{1}{1998}.\left(\frac{2}{7}+1\right)\)

= \(\frac{1}{1998}.\frac{9}{7}\)

= \(\frac{1}{1554}\).

\(\frac{3}{7}-\frac{5}{1998}.\frac{1}{7}\)

= \(\frac{3}{7}-\frac{5}{13986}\)

= \(\frac{5989}{13986}\).

Chúc bạn học tốt!