G5 Math Olympiad Part C

5. Find the missing number:

Use smart way to add: 531 + 642 + 753 + 864 + 975.

The first 40 odd counting numbers are written. How many times does ‘3’ appear as a digit?

Ashley has a rectangle made out of paper that is 8 cm by 12 cm. She folds it in half twice, first vertically and then

horizontally. The new rectangle looks just like the original rectangle but smaller. What is the area of the new smaller rectangle in square cm?

In the figure, the whole numbers from 1 through 7 are to be placed, one per square. The sum of the numbers in the left column, the

sum of the numbers in the right column, and the sum of the numbers in each diagonal are the same. What is the least possible product of the numbers across the gray row?

In the following cryptarithm, each different letter represents

a different digit in the 6-digit numbers. If B ≠ 0, what is the least sum possible?

Identify the figure in which the problem figure is embedded/hidden.

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Each of the following four large congruent squares is subdivided into combinations of congruent triangles or rectangles and is partially shaded. What percent of the total area is partially shaded?

• 20

• 25

1. A palindrome reads the same forwards and backwards. The number 2017102 is a 7-digit palindrome. Let A represent the least palindrome greater than 2017102. Let B represent the greatest palindrome less than 2017102. Find A – B.

Thirty-six points are arranged in a unit-square array as shown. Figure ABCDE is composed entirely of straight-line segments with vertices A, B, C, D, and E.

Find the number of degrees in the sum of the interior angles of figure ABCDE. [The interior angle at D is a reflex angle whose measure is greater than 180°.]