Bài 1: Tính nhanh a)40+30+60+70 b)10+80+90+20 c)25*8*4*125
2 câu trả lời
Bài ` 1 ` :
` a) 40 + 30 + 60 + 70 `
` = ( 40 + 60 ) + ( 30 + 70 ) `
` = 100 + 100 `
` = 200 `
` b) 10 + 80 + 90 + 20 `
` = ( 10 + 90 ) + ( 80 + 20 ) `
` = 100 + 100 `
` = 200 `
` c) 25 xx 8 xx 4 xx 125 `
` = ( 25 xx 8 ) xx ( 4 xx 125 ) `
` = 200 xx 500 `
` = 100000 `
a, 40 + 30 + 60 + 70
= (40 + 60) + (30 + 70)
= 100 + 100
= 200
b, 10 + 80 + 90 + 20
= (10 + 90) + ( 80 + 20)
= 100 + 100
= 200
c, 25 × 8 × 4 × 125
= (25 × 4) × (125 × 8)
= 100 × 1.000
= 100.000
