Bài 7: Tính nhanh c) 3. 25. 8 + 4. 37. 6 + 2. 38. 12 d) (1200 + 60) : 12e) 12.53 + 53. 172 – 53. 84 g) (2100 – 42) : 21h) 39.8 + 60.2 + 21.8 i) 36.28 + 36.82 + 64.69 + 64.41k) 32. 47 + 32. 53 l) 37.7 + 80.3 +43.7m) 113.38 + 113.62 + 87.62 + 87.38 n) 123.456 + 456.321 –256.444p) 43.37 + 93.43 + 57.61 + 69.57 q) 38. 63 + 37. 38r) 35.34 +35.38 + 65.75 +...
Đọc tiếp
Bài 7: Tính nhanh
c) 3. 25. 8 + 4. 37. 6 + 2. 38. 12 d) (1200 + 60) : 12
e) 12.53 + 53. 172 – 53. 84 g) (2100 – 42) : 21
h) 39.8 + 60.2 + 21.8 i) 36.28 + 36.82 + 64.69 + 64.41
k) 32. 47 + 32. 53 l) 37.7 + 80.3 +43.7
m) 113.38 + 113.62 + 87.62 + 87.38 n) 123.456 + 456.321 –256.444
p) 43.37 + 93.43 + 57.61 + 69.57 q) 38. 63 + 37. 38
r) 35.34 +35.38 + 65.75 + 65.45
c, 3.25.8 + 4.37.6 + 2.38.12
= (3.8).25 + (4.6).37 + (2.12).38
= 24.25 + 24.37 + 24.38
= 24.(25 + 37 + 38)
= 24.100
= 2400
d, (1200 + 60):12
= 1200: 12 + 60: 12
= 100 + 5
= 105