Kate is using fraction strips to add ##4/10## and ##4/5##. She uses one whole strip to represent the sum. How many fifths strips does she need to complete the sum?

Six

Four tenths strips represent ##4/10##. These are equivalent to 2 fifths strips. Now ##4/5## equal to 4 fifths strips. Thus to add the given fractions Kate has to use (2+4)= 6 fifths strips.