What do you notice? What do you wonder?

+	98	99	100	101	102
98		197		199
99	197		199		201
100		?		?
101	199		201		203
102		201		203

Here are 2 algorithms for adding .

Han’s algorithm

Elena’s algorithm

Discuss with your partner:

1. How is Elena’s algorithm different from Han’s algorithm?
2. Why do both algorithms work?

Here are 2 algorithms for adding .

Han’s algorithm

Elena's algorithm

1. How do the algorithms show the 14 tens differently?

2. Try using Elena’s algorithm to find the value of each sum.