Give your little one the opportunity to dive deeper into addition with this add 2-digit numbers and multiples of 10 worksheet. If the missing number is an addend, students use the count on strategy or the relationship between addition and subtraction to find the missing number. And if the missing number is the sum of the addition sentence, they add the addends to get the sum. This worksheet, add 2-digit numbers and multiples of 10, provides plenty of practice with this concept. In each problem, the numbers are laid out in the horizontal format. Students should try to use different strategies involving composing and decomposing numbers to solve these problems. This will help them develop flexibility and fluency.