Problem Solving

Manu collected 183 stamps in January. By March he had 834. How many stamps did he add to his collected in February?

834 - 183 =

800 - 180= 620

34 - 3 = 31  620 + 31 = 651

 Since I couldn't subtract 30 with 80, I combined 80 and 100 which is =180 So 800 - 180= 620 and now the only numbers left is 30, 4 and 3. So I put 30 and 4 together which is = 34. Finally I did 34 - 3 = 31 ( 620 + 31= 651)  

By Soane