4.)star liked to practice her number sense when possible. She
wanted to add two 2 digit numbers in her head. She thought 50 + 10
= 60 and 6+ 7 = 10 + 3. Then she was able to write down the correct
answer. Which problem was she solving?

56 + 17

Step-by-step explanation:

The numbers could be

56 + 17   because Star was separating how she added the decimal places

She added the tens units first and then the ones units last.

so   50 + 10   first

and then 6 + 7

$119.20

step-by-step explanation:

$372.50 - 60% off is $149. $149-20% off is $119.20

the circumference of a circle is, 10.676 cm.

step-by-step explanation:

the formula for circumference of a circle is given by:

where

c is the circumference of a circle and

d is the diameter of a circle.

given: diameter(d) = 3.4 cm and use

substitute these values in [1] we get;

cm

therefore, the circumference of a circle is, 10.676 cm