\(a,4 , 86 × 0 , 25 × 40\)
\(= 4 , 86 × ( 0 , 25 × 40 )\)
\(= 4 , 86 × 10=48,6\)
\(------------------\)
\(b ) 96 , 28 × 3 , 527 + 3 , 527 × 3 , 72\)
\(= 3 , 527 × ( 96 , 28 + 3 , 72 )\)
\(= 3 , 527 × 100=352,7\)
\(------------------\)
\(c ) 0 , 8 × 96 + 1 , 6 × 2\)
\(=(0,8×2)×(96:2)+1,6×2\)
\(=1,6×48+1,6×2\)
\(=1,6×(48+2)\)
\(=1,6×50\)
\(=80\)
\(------------------\)
\(d ) 72 , 9 × 99 + 72 + 0 , 9\)
\(= 72 , 9 × 99 + 72 , 9\)
\(= 72 , 9 × ( 99 + 1 )\)
\(= 72 , 9 × 100=7290\)
\(------------------\)
\(e ) 2 , 5 × 7 , 8 × 4\)
\(= ( 2 , 5 × 4 ) × 7 , 8\)
\(= 10 × 7 , 8=78\)
\(------------------\)
\(ê ) 0 , 5 × 9 , 6 × 2 \)
\(= ( 0 , 5 × 2 ) × 9 , 6\)
\(= 1 × 9 , 6=9,6\)
\(------------------\)
\(n ) 8 , 36 × 5 × 0 , 2\)
\(= 8 , 36 × 1=8,36\)
\(------------------\)
\(m ) 8 , 3 × 7 , 9 + 7 , 9 × 1 , 7\)
\(= ( 8 , 3 + 1 , 7 ) × 7 , 9\)
\(= 10 × 7 , 9=79\)
\(------------------\)
\(i ) 0 , 2 × 317 × 7 + 0 , 14 × 3520 + 33 , 1 × 14 \)
\(= ( 0 , 2 × 7 ) × 317 + ( 0 , 14 × 10 ) × ( 3520 : 10 ) + ( 33 , 1 × 10 ) × ( 14 : 10 )\)
\(= 1 , 4 × 317 + 1 , 4 × 352 + 331 × 1 , 4\)
\(= 1 , 4 × ( 317 + 352 + 331 )\)
\(= 1 , 4 × 1000=1400\)
a
= 4,86 x ( 0,25 x 40 )
= 4,86 x 10
= 48,6
b
= 3,527 x ( 96,28 + 3,72 )
= 3,527 x 100
= 352,7
c
= 0,8 x 96 + 0,8 x 2 x 2
= 0,8 x 96 + 0,8 x 4
= 0,8 x ( 96 + 4 )
= 0,8 x 100
= 80
d
= 72,9 x (99 + 0,9 + 0,1 )
= 72,9 x 100
= 7290
e
= 9,6 x ( 0,5 x 2 )
= 9,6 x 1
= 9,6
n
= 8,36 x ( 5 x 0,2 )
= 8,36 x 1
= 8,36
Ít thôi ;-;
4 và 5
