Let's do the math!

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Across
  1. 2. It is helpful to ________ the answer before doing the math.
  2. 4. 57 divided by 5 equals ______
  3. 7. 7 and 6 are _______ of 42.
  4. 9. Many people think this number is bad luck.
  5. 10. We do not ____ the decimal point when adding or subtracting fractions.
Down
  1. 1. This number is a prime number between 15 and 20.
  2. 3. All even numbers are divisible by ____
  3. 5. This number is a multiple of 5 and has the value of 5 nickels.
  4. 6. Five groups of ten and three ones
  5. 8. ______ is equal to 5 x 6.2 rounded to the nearest 10.