i)
27 × 121 - 87 × 27 + 73 × 34
= 27 × (121 - 87) + 73 × 34
= 27 × 34 + 73 × 34
= 34 × (27 + 73)
= 34 × 100
= 3400
j)
125 × 98 - 125 × 46 - 52 × 25
= 125 × (98 - 46) - 52 × 25
= 125 × 52 - 52 × 25
= 52 × (125 - 25)
= 52 × 100
= 5200
CHUK BN HỌC TỐT
XIN HAY NHẤT NHA!