Age:
8-9 years old

Aims:
To learn a different way to add numbers.

Introduction:
The teacher presnts a method for adding numbers with two digits.

• the two addends are placed in the top and bottom parts of a cross drawn on the board
• the numbers are decomposed into tens and units
• the units are written in the same part of the cross where the decomposed number is
• the tens are written in the free parts of the cross, the tens obtained from the number on top are on the left and those obtained from the number at the bottom are on the right
• the original numbers are crossed out
• the four remaining numbers are added

A pupils carries out an example on the board.