[r]
(1)VIOLYMPIC TỐN – VỊNG (23-11-2012) Tính nhanh:
1/ 42,75 × 39 – 42,75 × 29 = 2/ 1,986 × 41 + 1,986 × 59 = 3/ 20,08 × + 20,08 × = 4/ 1,386 × 194 – 1,386 × 94 =
5/ 0,028 × 93,27 – 0,028 × 83,27 = 6/ 29,34 × 87,56 – 29,34 × 77,56 = 7/ 28,54 × 3,8 + 28,54 × 6,2 = 8/ 1,1 × 20,9 – 20,9 =
9/ 265,3 × 0,06 + 265,3 × 0,04 = 10/ 26,9 × 28,41 – 26,9 × 28,4 = 11/ 14,58 × + 14,58 × = 12/ 37,91 × 39 – 37,91 × 29 =
13/ 8,192 × 154,09 – 8,192 × 54,09 = 14/ 58,07 × 6,78 – 58,07 × 6,68 = 15/ 20,08 × + 20,08 × =
16/ 0,396 × 74 + 0,396 × 26 = 17/ 25,86 × 17 – 25,86 × =
18/ 0,924 × 142,9 – 0,924 × 42,9 = 19/ 0,384 × 12,3 + 0,384 × 87,7 = 20/ 1,369 × 23,9 + 1,369 × 76,1 = 21/ 12,84 × 1,8 – 12,84 × 1,7 = 22/ 815,5 × 0,08 + 815,5 × 0,02 = 23/ 1,01 × 68 – 68 =
24/ 2,305 × 108 – 2,305 × = 25/ 1,472 × 81 + 1,472 × 19 =
(2)