Oppgåve 20

a) 8 × 26 = 8 × ( 20 + 6 ) = 208

b) 5 × 47 = 5 × ( 40 + 7 ) = 235

c) 9 × 39 = 9 × ( 30 + 9 ) = 351

d) 7 × 78 = 7 × ( 70 + 8 ) = 546

Oppgåve 21

a) 6 × 53 = 6 × ( 50 + 3 ) = 318

b) 96 × 4 = ( 90 + 6 ) × 4 = 384

c) 87 × 7 = ( 80 + 7 ) × 7 = 609

d) 6 × 73 = 6 × ( 70 + 3 ) = 438

Oppgåve 22

a) 6 × 98 = 6 × ( 90 + 8 ) = 588

b) 69 × 5 = ( 60 + 9 ) × 5 = 345

c) 4 × 59 = 4 × ( 50 + 9 ) = 236

d) 43 × 8 = ( 40 + 3 ) × 8 = 344