Use numbers to explain the pattern you see when you count forward by tens.

If you can count from 1-10, then you can count forward by tens. You simply continue the pattern 1-10, but add a zero at the end: 1 2 3 4 5 6 7 8 9 10 becomes 10 20 30 40 50 60 70 80 90 100. When you continue past 100, the pattern repeats in the tens place, and eventually in the hundreds place: 110 120 130 140 150 160 170 180 190 200. And so on and so forth.

D. triangular pyramid