=(360 + 40) + ( 135 + 65)
= 400 + 200
= 600
2. 463 + 318 + 137 + 22
= (463 + 137) + ( 318 + 22)
= 600 + 340
=940
3. 20 + 21 +22 + ... + 29 + 30
=(20+ 30) + ( 21+ 29) + ( 22+ 28) + (23+ 27) + (24 +26) +25
= 50 + 50 + 50 + 50 + 50 + 25
= 275
1)dap an do la .....
2)đáp án đó là...
3)đáp án đó là ...
đúng đấy mình đã tính kỹ rồi
1) 135 + 360 + 65 + 40
= (135 + 65) + (360 + 40)
= 200 + 400
= 600
2) 463 + 318 + 137 +22
= (463 + 137) + (318 + 22)
= 600 + 340
=940
3) 20 + 21 + 22 + .... + 29 + 30
= (20 + 30) + (21 + 29) + ( 22 + 28) + ....+ 25
= 50 + 50 + 50 + .... + 25
= 50 . 5 + 25
=250 + 25
=275
1) 135 + 360 + 65 + 40 = ( 135 + 65 ) + ( 360 + 40 )
= 200 + 400
= 600
2) 463 + 318 + 137 + 22 = ( 463 + 137 ) + ( 318 + 22 )
= 600 + 400
= 1000
3) 20 + 21 + 22 + .... + 29 + 30 = ( 20 + 30 ) + ( 21 + 29 ) + ( 22 + 28 ) + ( 23 + 27 ) + ( 24 + 26 ) + 25
= 50 . 5 + 25
= 250 + 25
= 275
1) 135 + 360 + 65 + 40
= ( 135 + 65 ) + ( 360 + 40 )
= 200 + 400
= 600
2) 463 + 318 + 137 + 22
= ( 463 + 137 ) + ( 318 + 22 )
= 600 + 340
= 940
3) 20 + 21 + 22 + ... + 29 + 30
= ( 20 + 30 ) + ( 21 + 29 ) + ( 22 + 28 ) + ( 23 + 27 ) + ( 24 + 26 ) + 25
= 50 + 50 + 50 + 50 + 50 + 25
= 50 x 5 + 25
= 250 + 25
= 275
1 . 135 + 360 + 65 + 40
= ( 135 + 65 ) + ( 360 + 40 )
= 200 + 400
= 600
2 . 463 + 318 + 137 + 22
= ( 463 + 137 ) + ( 318 + 22 )
= 600 + 340
= 940
3 . 20 + 21 + 22 + ... + 29 + 30
= 20 + 21 + 22 + 23 + 24 + 25 + 26 + 27 + 28 + 29 + 30
= ( 20 + 30 ) + ( 21 + 29 ) + ( 22 + 28 ) + ( 23 + 27 ) + ( 24 + 26 ) + 25
= 50 + 50 + 50 + 50 + 50 + 25
= 275
