CÁC DẠNG BÀI TÍNH NHANH Tính nhanh: Tính nhanh: a) (100 + 67) x 67 + ( 200 – 33) x 33 d) 72 + 36 x2 + 24 x + 18 x + 12 x + 168 Tính nhanh: c) ( 100 + 42) x 42 + (200 – 58) x 58 g) 124 x 76 + 12 x 248 i) 128 x 68 + 16 x 256 Tính nhanh: b) 128 x 68 + 16 x 256 g) ( 200 - 58) x 58 + ( 100 + 42) x 42 h) 50 – 51 + 40 – 41 + 30 – 31 + 60 i) 28 + 62 x a x ( a x – a : 1) + 28 x + 28 Tính nhanh: a) 100 – 99 + 98 – 97 + 96 – 95 + …+ – + d) 2011 + 2011 + 2011 + 2011 – 2008 x i) 14968 + 9035 – 968 – 35 k) 72 x 55 + 216 x 15 CÁC DẠNG BÀI TÌM X Tìm X a) x ( + x X) = 290 d) 128 x X – 12 x X – 16 x X = 5208000 e) x X + 3,75 x X + 1,25 x X = 20 Tìm X ab) 9,15 x X + 2,85 x X = 48 g) x ( + x X) = 210 c) (X x + 4) : = i) ( X – 12) x 17 : = 51 d) ( 15 x 28 – X) : = 200 Tìm X a) ( X x + 8) : = 10 g) 280 : ( + x X) = b) ( X + 5) x 19 : = 57 h) x ( 28 – x X) = 72 c) x ( 36 – x X) = 64 i) ( X – 15 ) x : = d) 72 : x X = 335 k) ( X : + 6) x = 70 e) ( X : + 50) : = 12 l) x ( + x X) = 140 Tìm X b) x ( 12 – x X) = 54 c) X x 39 + X x 11 = 1000 i) ( X x 25 + 2012) x 20 = ( 50 + 2012 ) x 20 ...c) x ( 36 – x X) = 64 i) ( X – 15 ) x : = d) 72 : x X = 335 k) ( X : + 6) x = 70 e) ( X : + 50) : = 12 l) x ( + x X) = 140 Tìm X b) x ( 12 – x X) = 54 c) X x 39 + X x 11 = 1000 i) ( X x 25... x X) = 140 Tìm X b) x ( 12 – x X) = 54 c) X x 39 + X x 11 = 1000 i) ( X x 25 + 2012) x 20 = ( 50 + 2012 ) x 20