Adding and Subtracting Whole Numbers: math test solutions, Grade 4 – download the PDF

1 Compute / 4 pts

1. Carry in the ones, tens, and hundreds: 9,441. (1 pt)
2. \(70{,}415 + 8{,}987 = \) 79,402. (1 pt)
3. Borrow across the zeros: 5,329. (1 pt)
4. \(60{,}000 - 24{,}318 = \) 35,682. (1 pt)

2 Estimate / 3 pts

1. \(8{,}000 + 4{,}000 = \) 12,000. (1 pt)
2. \(9{,}000 - 6{,}000 = \) 3,000. (1 pt)
3. Yes. 12,095 is very close to the estimate of 12,000. (1 pt)

3 Check the answer / 3 pts

1. \(3{,}644 + 4{,}756 = 8{,}400\), which is not 8,300. Ravi is wrong. (1 pt)
2. \(8{,}300 - 4{,}756 = 3{,}544\). (1 pt)
3. He forgot that the hundreds digit was reduced by 1 after borrowing. (1 pt)

4 Aquarium visitors / 3 pts

1. \(14{,}250 + 18{,}765 = 33{,}015\), then \(33{,}015 + 16{,}980 = 49{,}995\). 49,995 visitors. (2 pts)
2. \(18{,}765 - 14{,}250 = 4{,}515\). 4,515 more visitors. (1 pt)

5 School fundraiser / 4 pts

(a) Two bars: a long bar of 6,475 for the fair and a shorter bar for the bake sale, missing 3,850. (1 pt)

(b) \(6{,}475 - 3{,}850 = 2{,}625\) dollars. (1 pt)

(c) \(6{,}475 + 2{,}625 = 9{,}100\) dollars. (1 pt)

(d) \(15{,}000 - 9{,}100 = 5{,}900\) dollars. (1 pt)

6 Mystery number / 3 pts

Undo “subtract 1,909” by adding: \(9{,}000 + 1{,}909 = 10{,}909\). (1 pt)

Undo “add 2,578” by subtracting: \(10{,}909 - 2{,}578 = 8{,}331\). (1 pt)

Check: \(8{,}331 + 2{,}578 = 10{,}909\) and \(10{,}909 - 1{,}909 = 9{,}000\). The number is 8,331. (1 pt)