Surface area of a box
Add the area of all six faces of a rectangular box (8 by 5 by 3).
A box has three pairs of matching faces. The surface area is 2(lw + lh + wh). With l = 8, w = 5 and h = 3: 2(40 + 24 + 15) = 158.
Classic Graphing 84
Start on the main screen: Press 2nd then mode (QUIT) to get back to the home screen. Pressing clear on a menu also backs out of it.
Type 2 × ( 8×5 + 8×3 + 5×3 ), with the brackets around all three products.
2×(8×5+8×3+5×3)Press enter.
enter
You should see2*(8*5+8*3+5*3) 158
Natural Scientific 991
Start on the main screen: Press MENU, then 1 (Calculate) to return to the main calculation screen. AC clears the line you are on.
Type the same expression with the brackets and press =.
2×(8×5+8×3+5×3)=
You should see2×(8×5+8×3+5×3) 158
RPN Scientific 15
Start on the main screen: There is no menu to leave. Press the back arrow to clear a number you are typing, or CLx (g then back arrow) to clear the X register.
Work out 8 × 5, then 8 × 3 and add. Each ENTER keeps a number for the multiply.
8ENTER5×8ENTER3×+Add 5 × 3 and double the total.
5ENTER3×+2×
You should see158.0000
Tips
- The answer is in square units. The volume of the same box (8 × 5 × 3 = 120) is in cubic units.