4 x 10 21 July 8, 2019 16 32 64 128 4 7 x 10 21 (- 3 4 x (- 10 21 3 4 x 21 )= 10 1 2 2x 10 x 4 21 216 x 10 4 21.5 x 10 4 7 10 x 4 21 as a fraction 210 x 10 4 210 =( 20 x 4 10 1 4 x 10 puissance 21