This week in maths we have been looking at addition and subtraction using Dienes. We have used Dienes before and so were comfortable working with them. We have looked at a new way of checking our work by looking at factor families, estimation and looking at the inverse.
118 + 347
We made sure that we first made an ESTIMATION. 120 + 350 = 470
We then used the Dienes to CALCULATE the answer. 118 + 347 = 465
We then used the inverse to CHECK our answer. 465 – 118 = 347