Can you do these without a calculator? answers

Can you do these without a calculator - or an abacus for that matter - (and 194 others) in eight minutes?

a) 243,405

b) 255,696

c) 78

d) 128

e) 316.93

f) 150.87

Grade

6 - A - You are a superstar

5 - B - Very good

3-4 - C - Average

1-2  - D - Poor

0 - F Must try harder